The skin represents a unique immunologic organ poised to protect the host from invading organisms and environmental antigens. The skin is also an important target for a variety of allergic and autoimmune responses. Mast cells are key to the pathogenesis of urticaria, angioedema, and mastocytosis. Atopic dermatitis is the consequence of an immunoregulatory abnormality resulting in a skindirected T helper type 2 response. Allergic contact dermatitis is an example of classic delayed type hypersensitivity. Circulating autoantibodies against the epidermis are a key mechanism by which bullous skin diseases occur.
Leung DYM, Diaz LA, DeLeo V, Soter NA. Allergic and Immunologic Skin Disorders. JAMA. 1997;278(22):1914-1923. doi:10.1001/jama.1997.03550220120016