Food Allergy Treatments

Non-drug therapy

Diet avoidance: avoiding the suspected food as much as possible.

Dietary Counseling: educating about allergens and maintain a balanced diet as possible.

Dietary manipulations: if pseudoallergic the elimination diet is followed by a reintroduction every 3 days of a new food.

Emergency drug therapy

Allergy emergency kit: Patients who have an allergy type I and may develop an episode of anaphylactic: The kit should contain an "auto injector of epinephrine," antihistamine and steroid injections, a profit warning in your documents the type of allergy.

Doses of adrenaline

Adult

0.3 mL IM in G. 1:1000 aqueous injection, the normal range is 0.2 to 0.5 mL in 10-15 min. It may be necessary to reduce the dose of 0.2 ml in the elderly or with known heart problems.

device self-injection 0.33 mg (0.33 mg Fastieckt) in the prescription range H

Pediatric

IM dosing in children is based on weight: 0.01 ml / kg IM 1:1000 dilution, not to exceed 0.3 ml IM in 1:2000 dilution in 10-15min.

self-injection device, 0,165 mg (0.165 mg Fastieckt) in the prescription range H.

Symptomatic drug therapy

Antihistamines: are currently used both in the maintenance phase in both the acute phases. Can cause sedation, individuals engaged in risky activities requiring alertness (eg driving), especially the older generation preparations.

Leukotriene modifiers

: they display in the allergic lung, their use in food allergies should be considered experimental.

Steroids

: in the acute phase of allergic reactions. Are by far the most effective drugs on the symptoms of food allergy in general and on 'inflammation, but are burdened by significant systemic side effects, especially with prolonged use. The doses of these drugs vary between different molecules as a function of equivalence ratio between the various steroid dosage, and above depending on the severity and type of pathological event.

Cromolyn sodium or DSCG or Cromolyn: in patients with gastrointestinal symptoms and signs should be used in the maintenance phase prophylactically to prevent or reduce the recurrence and severity,  has the characteristic not to be absorbed orally, and have an excellent tolerability.

In eosinophilic esophagitis sodium cromoglycate shows some efficacy. Moreover, in children with atopic dermatitis for the use of the same os is able to reduce intestinal permeability to macromolecules pathological allergy, while it is controversial to this day, the use topically.

Sodium cromoglycate or Cromolyn sodium for oral use (in the form of ampoules) in the U.S. is indicated in systemic mastocytosis, a rare serious illness, succeeding in this disease to relieve symptoms associated with gastrointestinal.

Food Allergy Treatments

 Etiological therapy

∙ Oral desensitization therapy is recommended only in cases of confirmed type I allergy to milk or eggs, not very effective for allergies to pollen, the doses of the allergen in this case must be increased regularly.

If there is a cross between a food allergy and pollen desensitization therapy is useful against pollen in 60% of patients.

Experimental therapies

∙ Immunization with plasmid DNA (PDNA)
∙ The use of probiotics such as Lactobacillus rhamnosus
∙ Allergen immunotherapy with heat-killed Listeria monocytogenes as an adjuvant, which induces the production of IFN-c
∙ Traditional Chinese medicine

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Food Allergy Treatments

Food Allergy Early Diagnosis and Psychological aspects

Food Allergy Diagnosis

Early Diagnosis
The diagnosis of food allergy is still based mainly on detailed medical history and complete physical examination of the subject. Clinical or laboratory tests serve only as an additional tool to confirm the diagnosis. The surveys include the standard skin tests such as skin prick tests and in vitro tests for specific IgE antibodies, and the oral tests by triggering food. The latter when properly executed will continue to be the gold standard in the diagnostic. Recently, non-conventional diagnostic methods are increasingly being used, but can not replace the previous, the risk that the results are not correlated with the cause of food allergy.

Psychological aspects
The lack of appropriate means of investigation of the psychological impact of food allergies in patients and their families, makes it difficult to quantify the implications of this disease frequently psychopathological risconttro especially youth in the population. It being understood that psychological factors do not allow us to predict the severity of symptoms in patients with hypersensitivity to food allergy.

The first study that confirms the presence of an 'association between allergies and mood disorders and' anxiety according to the criteria of the DMS IV is the Canadian study by Patten SB, Williams JV, and 2007. Lillestøl K, et al. 2010 evaluates depression and anxiety, with suitable scales and questionnaires, in subjects with a diagnosis of IBS and food allergy (self reported), noting with the criteria of DSM-IV anxiety disorder increased by 34% and 16 % for the depressive.

Herbert LJ, et al. in 2008 notes that in subjects with food allergy, who have experienced an episode of anaphylaxis from allergic subjects who had no episodes, self-esteem levels are lower and are detectable anxious and depressive traits, as well as indicating an episode of anafillassi can be a reliable indicator of psychological stress.

Food Allergy Diagnosis

- In celiac disease are found high rates of depression.

The use of medication for allergies (especially respiratory, including FDEIA) such as systemic corticosteroids or lucotrieni inhibitors are associated with high rates of insomnia, depression and even suicide risk, which requires careful monitoring in this regard by clinicians. The FDA has issued a warning in August 2009 (boxed warning) refers to the risk of suicide induced by inhibitors of lucotrieni: Montelukast, Zafirlukast and Zileuton.

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Food Allergy Diagnosis

Food Allergy Oral provocation test

The oral provocation test used to confirm the diagnosis of food allergy to a food.
It is conducted under medical supervision, is the administration of the suspect food orally in gradually, with careful assessment of any symptoms successors. In case of presentation of these you should be withheld and if administering medication. The tests were preceded by triggering an appropriate washout period of the suspected food, the test is conducted on the condition that the patient can not use drugs that interfere, also the test shall be performed in a hospital setting and is a good prudential rule that the patient has already made a venous access (catheter already inserted into a vein) for a possible rapid administration of rescue medication in case of shock successor.

The most reliable method is to conduct double-blind (neither the patient nor the doctor must know who is the champion with the offending food), but often we accept the single-blind, questocaso only the patient knows who is the champion with the offending food.

The tests are carried out when no outbreak is suspected or when a reaction anfilattica allow the tests already carried out a diagnostic certainty of food allergy in relation to the offending food.

The various types of oral provocation tests are:
tests in the open: the food is taken in the usual way, but when the result is ambiguous to perform the test in a blinded fashion.

single-blind tests: the suspect food should be mixed with other foods and should not be recognized by the patient in this case an error of assessment by the physician subjectivity is possible, as this error is considered to be statistically small.

double-blind placebo test: the suspected food is placed in capsules, they are of 2 types: with food and without food. These days are to be taken away from each other. With this type of examination the error evaluation of the physician and the patient is minimized. This method is measured the decisive factor set for diagnosing food allergy, and is used primarily in research surveys. He is currently the simply absolutely objective way to be sure of an unsympathetic reaction to food.

Food Allergy Serology

Serologic tests in vitro are easily performed, but some are made with a radioimmunoassay method which complicates somewhat the test and increases costs.

Eosinophil count
In order to make the eosinophil count should be done before a differential diagnosis: infection (due to high number of neutrophils), with congenital anomalies of the turbinate bones, with the irritation irritants, and other etiologies of non-allergic.

Although the number of eosinophils differential count can be achieved as compared to the total number of leukocytes, are used to count themselves more sophisticated methods that color specifically eosinophils (Tannen Pilot or solutions). The total number of eosinophils per mm 3 range from 0 to 450 in adults, in children from 50 to 700 and from 20 to 850 in the newborn.

Total dose of IgE
A high level of serum IgE may confirm the suspected diagnosis of an allergic disease. Since, however, there is a degree of overlap between the values ​​of IgE in allergic and in normal subjects, a normal amount of IgE does not exclude a diagnosis of allergies.

Currently IgE are measured with a radioimmunoassay method: the so-called PRIST (Paper Radio Immuno Sorbent Test or tests of radio-immuno-adsorption on paper). This test uses a solid substrate of paper, they are bound IgE antibodies. after appropriate washing, if they are present in the test serum IgE, these are linked by antibodies attached to the disk of paper. Using anti-IgE antibodies labeled with 125I. securing the IgE bound to the disc and then, after a further washing step, the readings of the disk of paper in a counter for gamma emissions.

The radioactivity of the complex will be directly proportional to the concentration of IgE in test serum. In adults the normal values ​​of serum IgE are less than 0.025 mg / dl.

Determination of specific IgE
It is more important than the dosage of total IgE, in fact, it is useful to confirm doubtful cases, and especially to skin tests for evaluation in young children or people with serious skin diseases.

It uses a test called RAST (Radio Allergo Sorbent Test, tests of radio-allergic-absorption) that has some similarities with PRIST. The allergen is covalently linked to a disk of paper and reacts with specific IgE antibody may be present in the test serum. After non-specific IgE were removed by washing, adding anti-IgE antibodies labeled with 125I, which bind to the complex hard-allergen-IgE. It reads at this point the radioactivity in a gamma counter for broadcasters. This will be proportional to the amount of specific IgE present.

The RAST is less sensitive but more specific than the skin test, and now the new laboratory techniques such as the CAP FEIA or UniCAP Sistem, have high sensitivity and ease of use.

House rapid methods
Point-of-care tests recently have proven practical methods for their self study at home (point of care testing), among them in the field of allergy merits signaling equipment of a Swedish Company: ImmunoCAP Rapid (ICR). This apparecchietto similar to a blood glucose meter for home blood glucose analysis, analyzing a drop of peripheral blood and is useful for the diagnosis of the first level: asthma, eczema and rhinitis. Among the food allergens tested include: eggs, milk, along with other common food allergens.

The reproducibility of the data is good, with a false positive rate of 1%. The tool is therefore useful for a first outpatient diagnosis of the most common allergies, especially in the respiratory tract.

Food Allergy Skin Tests

They are currently used for the diagnosis of food allergies are the most common screening test for food allergies and can also be performed on infants in the first months of life (Sopo reliable, however after 3 years). However, the reliability of the results depends on many factors, such as the use of allergens should be tested together with a precise technique of administration, and concomitant medications that may interfere with tests such as for example: antihistamines or cortisone.

When these tests are used with appropriate controls as standard, for example, a test with a positive sample on the basis of histamine and a negative-based saline; provide precise criteria for the diagnosis easily reproducible with minimal cost and with negligible risks for patients . This method is generally reliable for excluding immediate food allergies, with a predictive accuracy of 90% if the result is negative, while this accuracy drops to 50% if positive. This limits the interpretation of clinical results, and then together with in vitro tests should also consider the history.

The result is always confirmed by a test read ministration incorminato food, unless the patient already has a history of allergy to some food.


Method

The intradermal tests are:
∙ prick test
∙ prick by prick (English: to prick prick =)
∙ scracth tests
∙ patch testing.

These are used both for food allergies and for respiratory allergies.

For the interpretation of the tests required experience and expertise, and the results obtained, in fact, should always be related to symptoms and history of patients and often require additional testing to establish a diagnosis of certainty.

During the execution of these tests you need to keep on hand an emergency kit, it can, albeit rarely, severe reactions occur, up to anaphylactic shock.

The skin prick test, if repeated several times with the same allergen, in turn, can cause sensitization.

The prick by prick is used only for food allergies in this method the needle used to scratch the skin of the patient is pre-inoculated in the food you want to test (fruit or vegetables).

Scracth The test is similar to the skin prick test but is less sensitive and more long-running, so now little used. After cleaning the skin with a sharp instrument practice is a slight scratch (in English, scratch) of 2 mm in length without bleeding, after which a drop of solution containing the allergen is placed above the lesion caused and gently you make a scratched rubbing the area to make it the solution to penetrate into the lesion, the reading is done after 10-30 min.

The patch test is indicated in the diagnosis of allergic contact dermatitis. It consists in the skin of the back of medicated patches with the allergen, they are routinely tested 31 allergens. The patch is removed after 24-72 hours, and check whether the application area of ​​skin redness occurred. This test is used in food allergies to ensure responsiveness to food in case of eosinophilic esophagitis, enterocolitis and atopic dermatitis. The value of this test, however, is uncertain and should be confirmed by more objective than those of studies conducted to date.

∙ Are made on the appropriate region of the forearm with thin-tipped hands that inject the allergen to be tested, it is important to use a lancet for each allergen, respecting the minimum distance between an allergen and another (2.5 cm).

∙ Comparisons are made ​​with the negative controls with saline and positive control with histamine (10 ng / mL in G. Physiological).

∙ The reading should be done after 5 min for histamine and after 15 for allergens, it is advisable to use a stopwatch. They are of dubious responses that occur after 15-20 min.

∙ The tests are not very risky, but it is good to do a preliminary test with the allergen is not inoculated subcutaneously with the needle and see if looks like a reaction, in which case you should not test for the risk of a severe reaction type anaphylactic (as well as the uselessness of the test in this circumstance).

Limitations of skin testing
In general, these tests are used on individuals aged less than 3 years. However, should not be made ​​in the following cases:

1. lesions from scratching or skin diseases in the area of administration of the test.

2. dermographic patients, for a heightened responsiveness on the part of the skin from these patients.

3. use of antihistamines and / or steroids and / or immunosuppressive agents, which inhibit the immunological mechanisms and thus the reactivity of the skin (may have the same effect, although a much lesser extent, beta-blockers).

Food Allergy Tests and Laboratory Tests

Diet Diary

The diet diary is to keep a log of foods eaten in chronological order and associated with adverse effects and symptoms associated with food intake.

It is easy to implement a system inexpensive to document the frequency and the relationship of cause / effect taken with food, with the advantage of focusing the patients on the correct management of their diet.

The diagnostic utility is restricted, especially if food reactions occur after some time of their recruitment.

This post is also rarely useful to identify foods implicated in an adverse reaction, it does not allow to make the diagnosis with certainty especially when the symptoms are delayed or rare.

Elimination diet
It is commonly used to make diagnosis and therapeutic purposes.
Its use for diagnostic purposes is to eliminate all foods or food groups suspected for a certain period of time (7-10 days) concomitantly with a decrease in symptom control.

The elimination diet is more useful in evaluating chronic conditions. The success of this depends on the certainty of having eliminated the suspected food from the diet. The limitations of this method are related only to the prejudices of the physician and patient, especially if over time the patient can not stand the limitation that this diet entails.

Once allergens are identified, they are removed from the patient's diet indefinitely, unless the resolution of the disease over time.

Food Allergy Comorbidities

Immunological and rheumatological: vasculitis (found an association with Henoch-Schonlein purpura) , arthritis: in particular it was noted that in the intestinal mucosa of patients with juvenile idiopathic arthritis are activated cytotoxic lymphocytes, similar to what occurs in the course of allergies. This may suggest a possible role of food allergens in the pathogenesis of this disease.

Neurological and psychiatric disorders: migraine (between the various pathogenetic hypotheses many authors have assumed the role of some food allergens). Among the patients was also an increased incidence of mental disorders such as anxiety, depressive symptoms, aggression and sleep disturbances, as well as an increased risk of suicide.

Renal and genitourinary: in some cases of enuresis the child was observed an effect of particular foods trigger. Even some forms of nephrotic syndrome may have a link with allergy: in particular it has been hypothesized that the 'interleukin 13, a cytokine involved in IgE-mediated immune response, may be responsible for proteinuria in patients with minimal change glomerulopathy in the its ability to induce the expression of a molecule called CD80 on the surface of podocytes.

Among the allergens identified as potential underlying causes of nephrotic syndrome (especially in childhood) are the milk proteins.

ENT: recently (May 2010) were reported as uncommon complication in the course of food allergy, allergic rhinitis.

Genetics of food allergy

Food allergy may be at least partly genetically determined. The risk of Peanut.Allergy, for case in point, with reference to 10 times higher in a child by means of a sibling as well is allergic to peanuts than the wide-ranging population, but to date no precise genes have been identified. So even for non.IgE mediated food allergy, in which there was a large ethnic difference in the incidence and family, with the predominance of male Caucasians.

In families where more than one parent has allergies, the risk to children have food allergies is very high, even if you can not predict food allergies than other types of allergy.

∙ 80% chance of allergy if both parents are atopic manifestations associated with several (eg, asthma and food allergy combined)

∙ 40 -60% chance of allergy if both parents are atopic

∙ 25 to 40% chance of allergy when only one parent is affected by allergy

∙ 20 to 25% chance of allergy when a brother is allergic

Location of events
The T cells reside permanently in the target organs may explain why some foods are localized allergic diseases, and have no systemic features as in the case of atopic dermatitis and eosinophilic esophagitis. The events and the most prevalent of food allergies are the result of a complex, not entirely known, mechanism of relationships between host, environment, food and genetic causes, so what, this, among other things that makes difficult the development of causal therapies.

Types of food allergies

Commonly mechanisms due to food allergies and the resulting classification made on the basis of the etio-pathological mechanisms is divided into three categories:
∙ IgE-mediated
∙ non-IgE mediated,
∙ mixed.

Typically, municipalities and "major" food allergens responsible for IgE-mediated forms are glycoproteins soluble in water, with sizes ranging from 10 to 70 k Dalton , they are relatively stable to heat , to acids , and proteases of the gastrointestinal tract.

In addition, the presence of other immune factors in food can also contribute to raising immunological gender. For example, the allergen is a glycoprotein of peanut ( Ara h 1 ) that not only is awfully steady and opposing to heat and digestive-enzyme deprivation, but also acts as an adjuvant of T-lymphocytes helper2 (TH2) due to the expression of a "glycan adduct". The ' innate immunity in the intestine is represented by: natural killer cells , polymorphonuclear leukocytes , macrophages , epithelial cells in fell'orletto spazola, Toll-like receptors and acquired immunity, however, is represented by lymphocytes from the intraepithelial and lamina propria , from Peyer's patches , the IgA , and cytokines , together provide a barrier that can block the entry of antigens.

It is known that food allergy is more common in children: in fact most of the intestinal mucosal permeability in infants and early exposure to allergenic antigens have been proposed as a possible cause of sensitization in infants. However, it was shown that the gastrointestinal mucosa reaches its full maturity in terms of permeability after only 2-3 days after birth and the increased permeability observed in some children with food allergy seems to be more a consequence than the cause of the response inflammatory-type reactions.

In contrast, early exposure to foods may prevent the development of food allergies in some conditions. This is suggested by a recent study has shown that Israeli children, who often consume a popular snack of peanut before 1 year of age, have a prevalence 10 times lower in developing peanut allergies than children of Member U.S. and UK, where peanuts are consumed rarely before 12 months of age, have been proposed for this reason, other additional factors as needed to overcome the physiological oral tolerance.

Among the factors that can reduce food tolerance to food allergens include:

∙ the increased permeability of the intestinal inflammatory mucosa;

∙ the increased permeability of the intestinal mucosa due to irritative phenomena to drugs (aspirin);

∙ the presentation of food-proteins for alternative routes such as skin or respiratory mucosa. In about one third of children with coexisting food allergy asthma ;

∙ altering the balance between TH2 and immunological ' major histocompatibility antigen (MHC). Often due to recruitment of proteins of cow's milk during lactation

This appears (due to a loss of function in regulatory determined by CD4 + , (TGF)-β , IL-10 , CD25 + (these are T cells regulators), in favor of CD8 + (which is a type of T cells suppressor). Alterations are due to an anomaly gene that regulates the expression of the factor FOXP3 ). The IL-4 seems to have a role in intestinal inflammation on the susceptibility regolatatorio being food allergy.

Among the factors triggering food have recently been hypothesized as a cause of allergies:

∙ decrease in immunological competence against generally bacteria / viruses / worms (the so-called hygiene hypothesis );

∙ imbalance in favor of omega-6 at the expense of omega-3 ;

∙ reduction in the intake of dietary antioxidants and increase / decrease of vitamin D in the diet.

Forms non-IgE mediated food allergies are a minority compared to the total and occur in the absence of demonstrable specific IgE antibodies to foods on skin or in the serum .

They are less well characterized, but are usually due to an acute or chronic inflammation in the gastrointestinal tract where eosinophils and T cells appear to play an important role in the genesis of pathological event. In patients with food.induce enterocolitis TNF-α plays an important role: in fact, it can be measured in vitro in monocytes of children with food protein-induced enterocolitis. Chung and contemporaries furthermore found increased discoloration for TNF-α in duodenal biopsies of children with food-induced enterocolitis.

For mixed forms such as eosinophilic esophagitis, eosinophils, and chemoattractants play a key role. In these subjects the eotaxin-3 is over expressed in 50% of the esophageal tissue compared to controls with chronic esophagitis.

Pathophysiological Mechanisms of Food Allergies

General

The manifestations of the immune response in the course of food allergy are highly variable between individuals, so much so that some individuals, while producing specific IgE in some hapten protein, show no symptoms after taking the food incriminated, although the increased intake is related to an increased risk.

The biochemical characteristics of a food alone can not explain its allergenicity. In fact the natural consequence of exposure to new foods is the development of a physiological immune tolerance . The oral immune tolerance depends on a barrier intact and immunologically active the entire gastrointestinal tract. This barrier includes the epithelial cells joined by tight junctions and a thick layer of mucus , as well as the ' brush border , also enzymes, bile salts , and peak pH degrading them to help make it less immunogenic protein antigens.

Assumptions enzyme
Among the factors responsible for the triggering of an event-related allergic guests there is the activity of PAF acetilidrolasi , enzyme that degrades PAF , and this causes an increase in the severity of anaphylactoid reactions.

Hypothesis-resistance protein
Among the factors to be considered the stability of food proteins to digestion and fragmentation of chemical / enzymatic intestinal absorption of certain seeds ( groundnuts , cumin , cashews ). These proteins, in fact, remain intact and can more easily trigger allergic reactions, food also very severe.

Assumptions acid hyposecretion
So closely related to the previous assumptions, the growing incidence of eosinophilic esophagitis, a form of food allergy, which has increased in recent years must seem attributable to the use of PPIs (proton pump inhibitors), and this decreased because the resulting chloride use of these drugs makes it more difficult digestion of proteins by the body resulting in increased permeability of the same proteins in the intestinal mucosa. The hypothesis although not yet confirmed by human studies, it is very plausible and interesting.

The scientific literature to support this effect is relatively large and recent: and correlates well with the hypothesis of the resistance protein.

Assumptions cytokine
A recent study relates the quantity of production of IL-9 with intestinal permeability to proteins and the subsequent exasperated response of mast cells. The IL-9, in fact, stimulates the release of histamine by mast cells and proteases and promotes the expression of FcεRI α. TNF also plays a role in the genesis of enteropathy of food allergies.

Assumptions Leaky gut
A large recent literature and lays the foundation for understanding the molecular causes of sensitization by food protein antigens in susceptible individuals. One of the predisposing factors, long hypothesized to gastrointestinal diseases is impaired barrier function, referred to as leaky gut.

The first-degree relatives of patients with inflammatory bowel disease (IBD) have an increased intestinal permeability in the absence of clinical symptoms.

Patients with food allergies who also have increased intestinal permeability, have increased the severity of their clinical symptoms. Although constitutive abnormalities in intestinal permeability were not always observed in patients with food allergy, it is assumed that environmental events, including infection and stress, can alter intestinal permeability and promote food antigen sensitization by.

Assumptions microbiological
Another issue recently highlighted correlates with food allergies, intestinal microbial balance dell'ecositema and host defense mechanisms. According to Japanese authors, in fact, to avoid excessive inflammatory reactions in the intestine play a role in the microbial components directly regulate the functions of mast cells through Toll-like receptors . This may explain the reason by which allergic reactions are a function of a non-symbiotic intestinal flora proper maintenance.

Recent research links the viral infection Reoviridae to cause immunological changes such as to trigger the pathological response of food allergies.

The protective role of probiotics in health human extends to a range of disease manifestations and among these there are the allergic reactions.

Probably all the assumptions described above contribute to varying degrees in etiopagenesi food allergies, and all offer important keys to understanding and research for understanding and finding solutions to this widespread disease of the well-being.

Food Allergy Pathogenesis

General


Pathophysiological Mechanisms of Allergic

The pathophysiological mechanisms of allergy own immediate hypersensitivity reactions of type I, which is the most serious clinical manifestation of anaphylaxis occur both as local and systemic reactions. The systemic reaction generally follows the intravenous administration of an antigen previously used in which the host has been previously sensitized, this leads to a state of shock, even fatal.

The local nature of the reaction varies depending on the input port of the antigen, it may take the form of a localized skin edema (allergic rash or hives ); nasal discharge and conjunctivitis ( allergic rhinitis and allergic conjunctivitis), hay fever or asthma and Gastrointestinal events (vomiting, diarrhea, abdominal pain).

The type I hypersensitivity reactions occur in two phases:

1. immediate phase
sensitization phase (first exposure to antigen)
phase tripping

2. being delayed or secondary
The mast cell (see picture) has a crucial role in the development of disease . It is anatomically placed in strategic areas for the immune response, such as blood vessels , the mucous membrane , the nerve . The mast cell activation occurs through a link between the receptors and IgE. Another important step in the process of cellular immediate hypersensitivity type I cells is determined by the Th2 : they receive the signal from the antigen-presenting cells ( macrophages and dendritic cells ), after which the Th2 differ and produce different cytokines ; the latter are used to activate the production of IgE by B cells (sensitization phase). Mast cells together with basophils express membrane receptors FcεR, with high affinity for IgE. When mast cells are coated with IgE on the surface after an initial sensitization phase, the subsequent contact with the antigen determines the relationship between 2 molecules of IgE and the receptor FcεR. This link (antigen + 2 IgE + receptor FcεR) determine an activation of the transduction signal cytoplasmic of mast cell Ca + + dependent, involving the fusion of vesicles lysosomal full of mediators , especially histamine , with the inner surface of the membrane of mast cell and subsequent release of chemical mediators stored (step tripping). These mediators are responsible for the symptoms of Type I hypersensitivity reactions both localized and systemic responses also active late-type.

Food Allergy: Chemical Allergens

Category: Dyes
Classification E : by E 100 and E 199
Allergens chemical: Quinoline yellow , yellow-orange S , Azorubine , amaranth , erythrosine , Ponceau 4R, patent blue , indigo carmine , brilliant black , red iron oxide , cochineal , tartrazine

Category: Preservatives
Classification E : by E 200 E 299
Allergens chemical: Sorbic acid , sodium benzoate , sodium metabisulfite , sodium nitrate

Category: Antioxidants
Classification E : by E 300 and E 321
Allergens chemical: Butylated hydroxyanisole (BHA), propyl-gallate, butylated hydroxytoluene (BHT), tocopherol

Category: Flavor enhancers
Classification E : E621
Allergens chemical: Monosodium glutamate

Category: Natural substances
Classification E : Various
Allergens chemical: Salicylic acid , biogenic amines , p-hydroxy-benzoic acid, esters, acids, fragrances

Food Allergy Etiology

Food Allergens

Main types of food allergens and their epitopes .

Food: Milk
Features: Common, especially under 3 years
Prevalent symptoms: 1, 2, 3, 4, 5 FDEIA, proctitis and enterocolitis
Tolerance: Camel's milk and donkey
Directive 2007/68/EC: It is also lactose

Food: Eggs
Features: Common, especially under 3 years; rare in adults
Prevalent symptoms: 1, 2, 3, 4
Tolerance: cooking (partial)
Directive 2007/68/EC: We also derived

Food: Peanuts
Features: Common, long lasting, often fatal
Prevalent symptoms: 1, 2, 3, 4, 5 from OAS to Shock
Tolerance: cooking (partial)
Directive 2007/68/EC: We also derived

Food: Soy
Features: Common
Prevalent symptoms: 1, 2, 3, 4, 5 OAS, FDEIA
Tolerance: cooking (partial)
Directive 2007/68/EC: It also derivatives (E322: Lecithin)

Food: Sesame
Features: Serious, common geographical areas
Prevalent symptoms: 1, 2, 3, 4, 5, OAS
Tolerance: cooking (partial)
Directive 2007/68/EC: We also derived

Food: Prawns
Features:
Prevalent symptoms:
Tolerance:
Directive 2007/68/EC:

Food: Clams
Features:
Prevalent symptoms:
Tolerance:
Directive 2007/68/EC:

Food: Cashew
Features: Common as nuts
Prevalent symptoms: 1, 2, 3, 4 OAS
Tolerance: cooking (partial)
Directive 2007/68/EC: It flavors except

Food: Hazelnut
Features:
Prevalent symptoms:
Tolerance:
Directive 2007/68/EC:

Food: Brazilian Walnut
Features:
Prevalent symptoms:
Tolerance:
Directive 2007/68/EC:

Food: Cherry
Features:
Prevalent symptoms: 1, 2, 3, 4
Tolerance: cooking (partial)
Directive 2007/68/EC: No

Food: Wheat
Features:
Prevalent symptoms: 1, 2, 3, 4, Celiac Disease, FDEIA
Tolerance: cooking (partial)
Directive 2007/68/EC: We also derived

Legend: 1 = skin; 2 = Respiratory, GI = 3, 4 = Systemic, 5 = death Anaphylaxis: Recently at the 'Congress of the European Academy of Allergy and Clinical Immunology in London are presented the results of research concerning new varieties of peanuts GM, which will reduce the impact of food allergies for a lower number of allergenic epitopes.

A recent paper EFSA , but are not conclusive, indicates in food GMO risk of a possible increase in the prevalence of food allergy for possible presence of modified proteins with immunogenic power.

Food Allergy Mortality and Morbidity

Food intake can also be fatal in people who have a history of asthma (especially those with poor control of symptoms), previous episodes of anaphylaxis with the incriminated food, lack of recognition of early symptoms of anafillassi and / or delay the use adrenaline.

Adolescents and young adults seem to be the population most at risk.
The mortality of milk intake has increased dramatically in recent years. The foods most frequently implicated are: peanuts, nuts, fish and shellfish, although other foods can cause anaphylaxis.

The most commonly reported symptoms are: itchy oropharynx , angioedema / swelling larynx , stridor , coughing , wheezing , asthma , rash, urticaria and angioedema. The fatal cases have: severe laryngeal edema, bronchospasm irreversible hypotension resist treatments (shock) or a combination of these. But sometimes you may have problems such as nausea , vomiting , diarrhea or constipation, depending on the subject, but also leads to sexual and relationship problems, especially in boys aged between 14 and 21 years.

A survey conducted at the emergency department of Charity Hospital Maggiore of Novara (in the period 1 January 2003-31 December 2006), including hospital admissions for anaphylaxis or food allergy; of 165,120 admissions to intensive care with 6107 cases of reaction suspected allergic; suspected cases of food allergy are: (1.4%) and food allergies (0.8%) cases of anaphylaxis.

Food Allergy Epidemiology

Food allergy has the highest prevalence in the first few years of life, affecting, in fact, about 6% of children under the age of three years. This tends to decrease with age, reaching 10 years of age the incidence is found in adults.

There are no known events related to race, sex among children is more involved than the male sex, while among adults it is more involved than women.

In younger children the foods that cause most food allergies are: cow's milk (2.5%), egg (1.3%), peanuts (0.8%), soybeans (0, 4%), fish (0.1%) and crustaceans (0.1%). Forms due to milk, eggs and soybeans, 80% of cases are resolved with the school age. In contrast, allergies to peanuts, nuts and fish are considered permanent, and 20% of children with these allergies has a resolution in 5 years, although recurrences are possible.

The Mount Sinai Medical Center-USA conducted a telephone survey of more than 13,500 people have reported an increase in food allergies to peanuts, with a prevalence that has increased from 1997 to 2008 from 0.6% to 2.1% in children essentially unchanged compared with rates in adults, even with the limitations on the type of research is indicative of the steady increase in children with this type of food allergy.

Adults but are more susceptible to allergies due to food: shellfish (2%), peanut (0.6%), peanuts (0.5%), and fish (0.4%).

Allergic reactions to food additives in non-protein foods are uncommon. The reactions to plants are relatively common with an incidence of 5%, but are generally severe. It is, also, reported an increase of allergy to sesame seeds, commonly used in bakery products.

Is given a family history of atopic disease and food allergies, although environmental factors have a decisive role in the onset of the disease, as evidenced especially for food allergy to peanuts.

In the USA, allergies are the sixth place among the most common chronic diseases , in addition, 2-3% of admissions are due to allergic reactions to drugs.

Skin allergy is the typical manifestation of food allergy, skin disease and are more common in children younger than 11 years, these forms have increased from 3% to 10% of the sixties of the nineties. Urticaria and angioedema cone cutaneous manifestations most common food allergies, affecting approximately 15% of the population each year. Finally, there are more than 100 people die each year in the U.S. for anaphylactic reactions caused by ingestion of food.

Food Allergy History

The first to identify adverse reactions to foods were Hippocrates (460-370 BC), who realized that the food could be due to pathological manifestations such as' rash and headache , and later Galen (131-210 AD) who seems to cure Food allergy sufferers.

In the early decades of the twentieth century have been identified allergies to milk protein and egg.

The knowledge must be seen in the history of food sull'allergia necessarily more general knowledge of allergy and of ' immunology as a medical science . In this key the first report came to us about the reaction to stings of wasps , which seems to have struck and killed the Egyptian pharaoh Menfis lived between 3640 BC and 3300 BC It seems, furthermore, that Nero should of his fortune ascent to the throne of the ' Roman Empire to an allergy to horses of his brother Claudius, which prevented him from riding together with the ' Emperor Claudius his father.

We have to wait for the early nineteenth century to see the first discovery about immunology as we know it today. It was John Bostock , in 1819 , to understand that the reaction to hay (known as " hay fever ") had nothing to do with the fever itself. Eighty years later, the English physician Charles Harrison Blackley he developed the first allergy testing , which takes the intradermal injection of the substance suspected. The response was positive after 30 minutes when it appeared an intense redness, local inflammatory response caused by the foreign agent (called " allergen ").

In 1902 the French C. Richet and P. Portier introduced for the first time the term of anaphylaxis as a cause of acute and severe response to substances foreign to the body as drugs. The first to introduce the term allergy was the Austrian pediatrician Clemens von Pirquet , after observing patients suffering from diphtheria.

The modern foundations of modern immunology as we know it today, originated in 1911 thanks to the doctors' L. Noon and J. Freeman, who sensed the therapeutic potential of vaccination desensitization therapy. In 1963 he was given the classification of allergic diseases by Philip Gell and Robin Coombs , and with it the four types of hypersensitivity reactions.

While the discovery of the first drug to allergies: antihistamines are the first in 1937 by Daniel Bovet. Then in 1949 there was the discovery of steroid hormones, by P. Hench with E. Kendall, these discoveries have laid the foundations for the treatment of allergy symptom in its manifestations. In subsequent years there have been the discovery of other molecules such as: cromones and leukotriene modifiers , these molecules, which have further broadened the baggage of medical treatment available today. In the near future we can expect news from the research front on ' genetic engineering.

In Italy the story of ' immunology has taken place thanks to the medical pioneers who were: C. Frugoni , G. Sanarelli and A. Zironi with their studies of the early twentieth century, while in 1954 we have the birth of Italy '"Italian Association for the study of allergy," later renamed "Italian Society of Allergy and Immunopathology".

Food Allergy

The allergic food reaction is a rapid and exaggerated pathology of the immune system against a food ingested. It is often mistakenly confused with the ' food intolerance (hypersensitivity or food). Schematically, the main differences are:

Pathology                              Causes (examples)
Food Allergy                           immune-mediated reaction to food proteins
Reaction: drugs / chemicals    caffeine , cheese / wine : tyramine , mackerel : histamine , food additives :
                                             preservatives , dyes , etc..     
Food-borne                             toxins bacterial stafilotossina
Food intolerance                     intolerance to lactose (deficiency of lactase ),
                                             intolerance to gluten : Celiac Disease

Manifestations of food allergy are observed in approximately 6% of children and 1-2% of adults, according to other authors, in Western populations, it is up to 8% in children and 2 - 3 , 7% Recent data from the U.S. CDC / National Center for Health Statistics show a dramatic increase of this disease. This disease, though rare, can manifest with clinical features such as life-threatening anaphylactic shock . Food allergies cause anaphylaxis potentially fatal, are due for 80% of cases to peanuts and nuts . The allergic reaction is determined by the food due to diverse symptoms that can occur in various organs and systems such as the skin , the ' gastrointestinal tract , the ' respiratory system . Allergic reactions involving the involvement of immune mechanisms, IgE- mediated and cell-mediated, in pathophysiological terms are part of the immediate type I hypersensitivity .

It is widely accepted that this disease is due to a suppression of the normal mechanisms of immunological tolerance to protein ingested with food. Among the foods most involved in food allergies, there are the milk , the eggs , the soybean , the peanuts , the nuts , the fish , the crustaceans and many other foods capable to degranulate the ' histamine contained in mast cells . For the diagnosis requires careful medical history , followed by laboratory investigations, and even if necessary to test triggering.

Usually the disease management is educating the patient to avoid the strict ' allergen responsible for allergic reactions and simultaneously, in case of unintentional ingestion of the same, start anti-allergic therapy. Sometimes it is also possible preventive drug.

Allergic Dermatitis

The dermatitis, allergic (or the eczema are allergic) is an inflammatory reaction (immune) of the skin, caused by a hypersensitivity of mast cells of the immune system to a substance ( allergen ) and / or congenital problems of synthesizing fatty acid gamma-linolenic ( neurodermatitis , atopic eczema ). It is not contagious, it is also called eczema.

Etiology

With respect to skin diseases is often difficult to distinguish from infectious forms of allergies, irritating or toxic. Often follows an allergy to fungal infection and / or bacterial skin flora caused by disturbed (lack of fatty acids and dry skin) and / or micro-lesions of the skin caused by clothing or scratching the affected area.

Sometimes it is the skin manifestation of food allergy, especially in children.

Symptoms

The dermatitis is usually manifested by redness, scaling, vesicles , blisters, abrasions and scabs. Sometimes the same patient has multiple injuries. The latter, initially present only in the area of ​​contact, can also be extended elsewhere. The itching is less important than the irritant contact forms.

Allergy Desensitization
The allergy desensitization is based on the use of identified allergens taken by the patient for long periods of time: one two three years. The determination of the allergen or allergens responsible for the allergic reaction can be identified at present with various tests such as the prick test or patch test, or the measurement of serum Rast for each or group of allergens, in addition to the total IgE assay.

Types of allergen

Nickel
The nickel is a metal found in many objects, such as sunglasses , necklaces, coins, wristwatches etc..

Chrome
The main source of chromium is the concrete , which is why many in the cement masons and workers are suffering from dermatitis. Chromium is also present in detergents in soaps, in fabrics, etc..

Cobalt
The cobalt is present in the cement and various metal alloys, inks, dyes, lubricating oils.

Dyes
They are used in textiles , in cosmetics , in leather processing, dyeing hair.

Resins
The resins are used in the fields of industrial , electrical , automotive , shipbuilding , etc.., but also in the preparation of surgical and dental implants.

Allergy Treatment

Although there is no cure for allergies, can sometimes a desensitisation to allergens through "vaccine", providing the patient with the allergen in question, gradually increasing the doses favoring the formation of IgG antibodies that block the antigen first accession to IgE . This therapy is commonly used only for inhalation allergies. However, there are specialized centers that practice successful desensitization for food allergies (well-selected cases).

You can also treat individual symptoms with drugs that inhibit the receptors of the H1 histamine (antihistamines such as cetirizine , the desloratadine and loratadine ). However, to achieve maximum effectiveness, this kind of medicine should be administered before exposure to the allergen.

They are very effective on the later phase of the action including anti-inflammatory drugs, such as cortisone (" prednisolone "," Betamethasone ") acting over a few hours. To minimize the side effects of steroids on a general, steroids are often used for local use (bronchial and nasal spray). The great advantage is determined by the very low incidence of side effects at the doses correct, and the ability to use very long (months or years to treat asthma).

Another category of anti-allergic drugs are cromones . It is a Mediterranean plant-derived products (Amni Visnaga) for local application that are administered as eye drops or nasal spray or aerosol sprays for the bronchi. Their action is to prevent the release of histamine and other irritants that would be released from special cells ( mast cells ) during allergic stimuli. The cromones are cromolyn sodium and the most recent sodium nedocromil . These also act when administered before contact with the allergen, and that is why their main use is in the prophylactic treatment of ' bronchial asthma , and only the sodium cromoglycate in the ' food allergies .

Another possible solution to tackle the problem of allergy is the Salbutamol is a selective agonist of the beta2-adrenergic receptors and is administered via aerosol before entering into contact with an allergen, or Albuterol Sulfate also known as Ventolin, having the same effect of salbutamol, only used in cases of need and in fact sold in the form of spray.

Some success have cromones : sodium cromoglycate and nedocromil , which have the ability to prevent degranulazionezione of histamine contained in mast cells .

Much more recent are leukotriene modifiers (eg montelukast), which are not specific for allergy medications being used especially in bronchial asthma (allergic or not allergic) but many studies are showing a good efficacy in allergic rhinitis. Their use for this condition is currently limited by the high cost.

The last frontier in the treatment of allergies are antiIgE antibody (omalizumab). These humanized monoclonal antibodies (not derived from humans, therefore, very sure) that recognize IgE as their "enemy" by fixing them and, thus neutralizing the effect. Are successfully used in bronchial asthma are allergic, but their widespread use is currently limited by the very high cost.

Drugs that are currently in the studio can act well before the release of histamine and in a highly selective, penetrating the interior of the cells involved in allergic reaction, and by selectively blocking only those activities that lead to the triggering of the reaction. In this way you are trying to get drugs even more effective and tolerable.

Allergy Symptoms and Diagnosis

Allergy Symptoms

Allergies are characterized by an inflammatory response to allergens , local or systemic. Local symptoms are typical:

Nose: swelling of the nasal mucous membrane and drain the liquid sneezing ( allergic rhinitis ).

Eyes: redness and itching of the conjunctiva ( allergic conjunctivitis ). Almost always it is a phenomenon accompanying allergic rhinitis.

Lower airways: irritation, bronchoconstriction, attacks' s asthma .

Skin: allergic dermatitis such as eczema , hives , atopic dermatitis (partially) and contact dermatitis .

Body problems: diarrhea or constipation, sexual and relational problems, and depending on the severity of regurgitation can cause serious heart problems.

The systemic allergic response is also called " anaphylaxis ": depending on the level of severity, can cause skin reactions, bronchoconstriction, edema , hypotension up to anaphylactic shock which may cause coma , sometimes lethal.

Allergy Diagnosis

The antibodies responsible for allergic reactions are the " IgE ", also called" reagin ". They are usually present in all individuals. The assay is performed with a blood test called PRIST (Paper Radio Immuno Sorbent Test). A high level of IgE in the blood directed towards allergy but can be found in people who are not allergic. The main test for the diagnosis of allergy skin test is the " prick test ". With such an investigation is made to contact a small amount of allergen with the skin of the patient gently milled with the aid of special hands by tiny bit. If the patient has IgE antibodies active against a specific allergen, you will see a reaction with itching swelling ( wheal ) at the substance to which the patient is allergic. Other investigations are utlilizzate RAST (Radio Allergo Sorbent Test) that seeks IgE directly into the bloodstream. The test triggering organ in which it causes the allergy experimentally by exposing the patient to the suspected allergen is commonly used for the diagnosis of allergic rhinitis and conjunctivitis.