Comparative research of skin prick test results between commercially available and home made food allergen extracts in patients with food allergy.

Since the mid-1990s, the Erasmus Medical Centre use home made food allergen
extracts for the diagnosis of an IgE-mediated allergy. The skin prick test with
these extracts is a fast and reliable method to confirm sensitization in the
patient. Commercial over the years fewer and fewer allergens from foods are
available, also these are usually not registered. Of the allergens that are
still available, the specificity and sensitivity is mostly unknown.
Right now home made extracts of foods and commercially available food extracts
can be compared with each other, this will be more difficult in the future. As
Department of Allergology we strongly depend on the home made extracts.

1. Testing comparability and reliability through skin prick test between home
made extracts and commercially available extracts of food allergens in patients
with suspected food allergy.
2. Comparing skin prick test results with home made extracts and commercially
available extracts of food allergens, and the specific allergic symptoms
reported by the patient in the questionnaire.
3. Comparing skin prick test results with serum IgE results.

From March 2018 we will perform skin prick tests with 4 different allergens,
patients will be tested with home made extracts and the commercially available
extract.
Research method: almond, apple, banana, shrimp, herring, hazelnut, codfish,
hen's egg, chicken, cow's milk, crab, peach, peanut, celery,
soya-bean, wheat flour, tomato, pork, walnut and carrot extracts will be
tested. The skin prick tests are performed on the forearm, the surface of the
skin reaction is measured and scanned. The skin reaction will be recorded in a
HEP (histamine equivalent prick test) index. The associated questionnaire
relating to the complaints is filled in.
Patient's blood (8 ml) will be collected for determining the serum IgE.

Patients meeting inclusion criteria will receive the information letter,
accompanied by an invitation for the first visit to the allergist. During this
first visit to the allergist, patients will be asked to participate in the
study. The appointment will take about one hour. 4 food allergens will be
double tested, the home made version and the commercial version. Due to the
skin prick test, a red, itchy lump might develop on the arm, which will
disappear automatically after 15 minutes.
A questionnaire will be completed.
A tube of blood (8 ml) will be collected through a venipuncture.