ABSTRACT
Alopecia areata (AA) is a chronic and relapsing hair follicle–specific autoimmune disease that leads to non-scarring hair loss. Topical contact immunotherapy was introduced by Rosenberg and Drake in 1976, and consists of the induction and periodic elicitation of allergic contact dermatitis (ACD) by applying a potent contact allergen onto the scalp of patients affected by AA. Sensitizers include any chemical for which the body develops immunity when exposed. Upon subsequent exposure, an inflammatory response is mounted by the immune system to fight off the chemical. Efficacy of topical sensitization for treating AA relies on four characteristics of the sensitizer: predictable immunomodulation , absence from the natural environment, lack of cross-reactivity with other substances, and, of course, safety. Clinical judgment must be exercised for each case since the treatment may be too irritating in patients with atopic dermatitis or those who have easily irritated skin.
