Skin Disorders Guide

Patients with porphyria cutanea tarda generally present with bullae and erosions on the dorsal surface of the hands. There is no inflammation surrounding the lesions. Blisters on the hands, which are identical with these (but without the accompanying porphyria), occasionally occur in patients taking tetracycline, nalidixic acid, furosemide (Lasix), and certain nonsteroidal anti-inflammatory drugs (NSAlDs). Similar bullae have been reported in patients with renal failure who are receiving dialysis. Some of these patients have elevated serum porphyrin levels. An idiopathic, immunobullous disease known as epidermolysis bullosa acquisita is also associated with the appearance of bullae on the dorsal surface of the hands. A rare childhood form of linear IgA disease is associated with pemphigoid-like blister formation. Identification is accomplished on the basis of immunofluorescent studies.

Bullae may occur as a part of the condition known as fixed drug eruption. Patients with this problem generally develop a single fairly large blister on an erythematous base each time they take certain medications such as sulfa-type drugs, phenolphthalein laxatives, and tetracycline antibiotics. The blisters recur in exactly the same location each time the drug is taken. In the male, fixed drug eruption is particularly likely to occur on the penis.

Trauma-induced blisters are encountered in the several genetically determined diseases of the epidermolysis bullosa group. These bullae arise from normal-appearing skin and develop following surprisingly modest degrees of friction. The diseases in this group are separately identified on the basis of inheritance pattern, histologic site of the blister, and the presence or absence of scarring at the time of healing. These diseases develop as a result of genetic defects in the various genes responsible for keratin production.

Diabetics occasionally develop blisters on the otherwise-normal skin of the lower legs and feet. Such blisters, known as diabetic bullae, seem unrelated to trauma, ischemia, or infection.