This 18-year-old African-American woman has a history of systemic lupus erythematosus. She developed a bullous eruption over her arms and face. Bullous lupus erythematosus is fairly rare, but when it occurs, is often in young African-American women, as in this case. The histology in this case is typical with a subepidermal cleft, dermal edema and inflammation with lymphocytes and neutrophils. Sometimes vasculitis is present. As with other forms of lupus, dermal mucin is increased. The histologic differential diagnosis would include dermatitis herpetiformis and linear IgA dermatosis. The direct immunofluorescence confirms the diagnosis, with linear or granular IgG and C3 deposited along the epidermal basement membrane, as was the case here (not shown).
Histologic sections of skin show separation of the epidermis from the dermis in a subepidermal plane. The epidermis is intact and viable. In the dermis, there is a moderately intense inflammatory component, in a perivascular and interstitial pattern. Scattered pigmented melanophages are also noted.