Diagnosis of dermatologic food allergy.

Fifty-seven children under 1 year of age, 43 children aged 12 to 35 months, and 42 children aged 3 to 15 years with atopic dermatitis were skin tested with foods suspected to have caused their dermatitis and other possible allergic symptoms. At least one positive skin test reaction was seen in 66% of the youngest children, in 21% in the second group, and in 50% of the oldest children. At least 24 out of 37 skin test-positive cases in the youngest group had allergic symptoms after ingested foods. The corresponding number among 1 to 3-year-old children was seven out of nine skin test-positive cases, and 14 out of 21 cases in the last group. Hen egg was the most common food allergen in children under 1 year of age. After that age, apple, carrot, pea, and soybean elicited positive reactions as often as egg. Among skin test-negative children there were five cases reacting with abdominal and skin symptoms to milk and one child who had abdominal pain and diarrhea after cereals. In conclusion, skin tests are often of great value in the diagnosis of dermatologic food allergy. Allergen avoidance diets and peroral challenge tests are needed for judging the clinical relevance of the skin test result and also for detecting untoward reactions to foods caused by other mechanisms than IgE-mediated atopic allergy.