Evaluating for Contact Allergies in Patients With Chronic Urticaria

Hives affects 10-25% of the population worldwide at some time during their lifetime. Hives are itchy transient swellings of the skin lasting 4-36 hours. Chronic urticaria is defined as hives that have been ongoing for six weeks or more. Patch testing is performed to diagnose allergic contact dermatitis, and if contact allergens are found via patch testing, patients can often be cured of their dermatitis. However, patch testing is currently not routinely performed in the evaluation of patients with chronic idiopathic urticaria. Our hypothesis is to see if contact allergens can be identified with patch testing in patients with chronic urticaria, and, if any allergens are identified, to see if avoiding these contact allergens will make the chronic urticaria go away.