Food-Specific and Component IgE Threshold Levels That Predict Food Allergy in People With Elevated Total Serum IgE Levels and Atopic Dermatitis

Background: Atopic dermatitis (AD), also called eczema, makes skin dry, red, and itchy. People with AD are more likely to get a food allergy than people without AD. But some food allergy tests are not always accurate in people with AD. Researchers want to study if people are truly allergic to milk and/or peanuts. Objectives: To improve the ways doctors test for food allergy in people with AD. Eligibility: People ages 3-21 who have had AD; have a high total IgE level (an allergic antibody); might have a milk and/or peanut allergy; and are currently enrolled in another NIH study Design: Participants will be screened under another protocol. Participants will have a physical exam, blood tests, and medical history. Participants will breathe into a plastic device that measures lung strength. Participants may get a small plastic tube inserted in their arm. Participants who have not had an allergic reaction to food in the past 3 years will do 1 or more oral food challenge (OFCs) depending on their allergies. They will eat a little bit of the food they might be allergic to. They will be watched for a reaction. If they have one, they will know for sure they are allergic. They may keep eating bigger portions of the food until they either have a reaction or finish all the food. In some OFCs, participants will get a placebo food. OFCs will last a few hours or 2 days. Participants will repeat all tests at each OFC. Participation can last up to 12 months. ...