The Feasibility of Systemic Reaction After Contact Exposure to the Allergenic Food in Children With Known Food Allergy

The prevalence of food allergy in the western world is a growing health problem. The majority of reactions are caused due to oral exposure to the known food allergen. However, there are reports about allergic symptoms after exposure to the allergenic food by contact and/ or inhalation. Most of those reports are subjective without an objective report of healthcare professionals. There are only a few prospective studies that observed objectively the "reliability" of those subjective reports. The estimated chance for systemic allergic reaction due to skin prick test with fresh food is 0.008%, and even then it will not cause anaphylaxis that will need epinephrine use. That evidence is in concordance with our experience. Even with all the information gathered, a study that examines the chance of systemic reaction after skin contact with the allergenic food is still missing.

Additionally, lately, researchers start to examine the influence of food allergy on the quality of life (QOL) of allergic children and their parents. As expected, all studies show negative effects on QOL. The major concern of the parents is from random exposure and severe allergic reaction due to contact with the allergenic food. As far as the investigators know, no study examined the influence of supervised contact with allergenic food on the fear of the child and his parents.

The study aims to evaluate the risk for a systemic allergic reaction after skin exposure to allergenic food in children with known food allergy.

The prevalence of food allergy in the western world is estimated at 8% and is constantly raising. The majority of reactions are caused due to oral exposure to the known food allergen. However, there are reports about allergic symptoms after exposure to the allergenic food by contact and/ or inhalation. Most of those reports are subjective without an objective report of a healthcare professional. There is one description of a 16-year-old boy with cow's milk allergy (CMA), who developed anaphylaxis from skin exposure to small amount of cow's milk under the supervision of a healthcare professional. There are only a few prospective studies that observed objectively the "reliability" of those subjective reports. In 2003, Simonte SJ et al examine 30 children with known peanut allergy of which 19 reported past reactions after contact/ inhaled exposure to peanuts. They did a supervised exposure to contact and inhalation of peanut butter. They reported only local skin reactions such as redness (10%), itching (17%), and wheal and flare (7%) with no systemic reactions. Other studies examine the allergic reactions to skin contact with peanuts and also did not report on systemic reactions. In one of the studies they examine the allergic reaction to skin contact in 330 children allergic to peanuts and only 41% had a local reaction with no systemic reactions. In the second study, the investigators did the accepted skin prick test (SPT) with peanut and immediate skin application food test (I-SAFT) with peanut butter in 84 children. The investigators did not observe systemic allergic reactions. Only one study examined allergic reactions after contact with cow's milk in children with CMA. The aim of this study was to compare the skin reaction of children with CMA with and without atopic dermatitis (AD). The investigators did not report systemic reactions also. There are few cases reports that described systemic allergic reaction during SPT, all cases were with fish allergy. A large study examined reactions to SPT with fresh food on 1,138 allergic patients. The investigators have shown that the chance of systemic allergic reaction is 0.008%, and none of the cases needed epinephrine. They review other 15 studies and did not find evidence to systemic reaction after SPT except for one study that reported a 0.005% prevalence of systemic reaction to follow SPT with fresh food in infants younger than 6 months of age.

That evidence is in concordance with the investigators experience. Until today, the investigators did not see the systemic reaction after SPT in children with food allergies. Even with all the information gathered, a study that examines the chance of systemic reaction after skin contact with the allergenic food is still missing.

Additionally, lately, researchers start to examine the influence of food allergy on the quality of life (QOL) of allergic children and their parents. As expected, all studies show a negative effect on QOL. The major concern of the parents is from random exposure and severe allergic reaction due to contact with the allergenic food. As far as the investigator know, no study examined the influence of supervised contact with allergenic food on the fear of the child and his parents.

The study aims primarily - to evaluate the risk for a systemic allergic reaction after skin exposure to the allergenic food in children with known food allergies.

secondary - 1. To evaluate the QOL of the parents (and children over 8 years) before and after the contact with the allergenic food.

Methods: 500 children with known food allergy and 100 children without food allergy as a control group. Simultaneously to the regular skin prick tests, a patch test sticker with the allergenic food will be placed on the forearm for 15 minutes. The parents will fill quality of life questionnaire before the tests, a week later, and 2 months later.

expected results - No allergic reaction will occur after the patch test other than mild local reaction. the level of anxiety will be reduced after the tests.

Eligibility Criteria:
Inclusion Criteria:

* Children aged one year to 18 years old with proven food allergy to one of the foods mentioned above.

Exclusion Criteria:

* under 12 months of age
* Admitted in the past in intensive care unit after allergic reaction
* Had allergic reaction that treated with three or more adrenalin doses (EpiPen/ IM adrenaline)
* Uncontrolled asthma (according to the GINA guidelines)
* Severe AD
* Children with allergy to three or more allergens not from the same allergen group