Allergic and reactive dermatoses. How to identify and treat them.

The epidermis, as the body's first line of defense against many pathogens, reacts in a variety of ways to the assault of foreign antigens. Allergic contact dermatitis, drug eruption, urticaria, and erythema multiforme are examples. The clinician must usually rely on clinical evidence for diagnosis. The first therapeutic strategy is to identify and avoid the antigen or drug causing the reaction. Beyond this, therapy consists of relief of symptoms in mild to moderate cases. In severe cases, systemic treatment can be helpful, but the therapeutic options and their efficacy are limited.