When people with AD are exposed to an irritant or allergen to which they are sensitive, inflammation-producing cells come into the skin. There, they release chemicals that cause itching and redness. Further damage occurs when the person scratches and rubs the affected area. All AD sufferers must avoid irritants, while those with known allergies should likewise avoid allergens. Detecting an allergic substance can be difficult, as discussed below.
Food allergies can cause flare-ups.
Diagnosing food allergies is extremely difficult. The surest way is to observe a worsening of eczema when a particular food is eaten. Sometimes this is only a coincidence with flaring and needs to be verified with a food challenge, where the suspected food is eaten in the doctor's office. Withholding foods should be done only under the supervision of a physician as serious nutritional damage can be caused by the elimination of foods suspected to cause flare-ups. Patients are seldom allergic to more than one or two foods.