Subcorneal pustular dermatosis: a clinical study of ten patients.

Subcorneal pustular dermatosis of Sneddon and Wilkinson (SPD) is a unique clinical and histologic entity. This disorder has been reported in association with monoclonal gammopathy and IgA pemphigus. We report ten additional cases of SPD and determine the frequency of monoclonal gammopathy and IgA pemphigus in patients with SPD and investigate the relationship of this entity with other dermatoses characterized histologically by a subcorneal pustule. The medical records of patients with SPD evaluated at the authors' institution from 1980 through 1995 were reviewed retrospectively. Medical records of twenty patients with pustular psoriasis were reviewed for comparison. Ten patients met the criteria for SPD. Their average age at diagnosis was 66 years. The characteristic flaccid pustules were often generalized and had a tendency to involve the flexural areas. Serum monoclonal gammopathy was present in four patients: three with IgA and one with IgG. On direct immunofluorescence examination, three patients had IgA deposits in the intercellular spaces. None of the patients exhibited both monoclonal gammopathy and IgA deposits. Repeated direct immunofluorescence studies were necessary to detect IgA pemphigus in one patient. SPD is a distinct clinical entity. The findings of IgA deposits intercellularly on immunofluorescence and monoclonal gammopathy may help to further identify this entity.