This study will evaluate children with allergies and collect medical data and biological specimens from them periodically to learn more about the diseases and gain information that may be useful in developing new treatments.

Patients 6 months to 18 years of age with a possible diagnosis of asthma, rhinitis, anaphylaxis, hives, atopic dermatitis, food allergy, stinging insect allergy, and other allergic and inflammatory diseases may be eligible for this study. Biological parents of patients may also be enrolled to provide a blood sample for genetic studies.

Participants undergo tests appropriate for the diagnosis and management of their allergy. They include the tests outlined below and, when necessary, additional blood tests, tissue biopsies (surgical removal of a small piece of tissue for microscopic examination), computed tomography (CT) or magnetic resonance imaging (MRI).

• Pulmonary function test: This test evaluates lung function. The patient blows hard into a tube attached to a machine to measure the airflow from the lungs. At home, the patient uses a small plastic device called a peak flow meter to measure lung function. Patients whose lung function measures less than 80 percent the value predicted for his or her age may be given the medicine albuterol to see if lung function improves.
• Skin prick testing: Drops of up to 55 different allergens (foreign substances, such as pollen and certain foods or medicines that cause reactions like sneezing, hives, eczema, and others) are placed on the back or arm. The skin under the allergen is then scratched with a pointed tool. If the person is allergic, the skin around the scratch develops a small area of itching, redness, or swelling that goes away after 30 to 60 minutes.
• Acoustic rhinometry: To learn the effect of allergies on the size of the nasal cavity, the nasal canal size is measured by placing a small round probe on the nostril. The device sends out and receives a sound wave signal from which the size of the nasal canal is calculated, recorded and stored graphically on a computer screen. The procedure is repeated three times with each nostril.
• Computerized assessment of learning and mood: Patients who are age 10 or older may take this computer test to find out if allergies affect learning and mood. The test measures the child's ability to understand directions, solve problems, and remember things. It also includes questions about how the child feels in general.
• Behavio...