Blisters of the skin have many origins, including bacterial, fun-gal, or viral infections; allergic contact reactions; burns; metabolic disorders; and immunologically mediated reactions. Some of these have been discussed previously (eg, herpes simplex and zoster in-fections, contact dermatitis). Immunologically mediated diseases are autoimmune reactions and represent a defect of IgM, IgE, IgG, and C3. Some of these conditions are life-threatening; others become chronic problems.
The diagnosis is always made by histologic examination of a biopsy specimen by a dermatopathologist. A specimen from the blister and surrounding skin demonstrates acantholysis (ie, sep-aration of epidermal cells from each other because of damage to or an abnormality of the intracellular substance). Circulating anti-bodies may be detected by immunofluorescent studies of the pa-tient‚Äôs serum.