Direct and indirect immunofluorescence are classically negative, but repeated investigation at suitable intervals is recommended to detect late onset intercellular IgA staining within the epidermis, which is referred to as IgA pemphigus or intercellular IgA dermatosis. IgA pemphigus is clinically indistinguishable from classical subcorneal pustular dermatosis. Subcorneal pustular dermatosis is a chronic relapsing condition. Most patients respond to dapsone, but not necessarily completely. Sulfapyridine and sulfamethoxypyridazine can be used as alternatives but are regarded as being less effective.
Corticosteroids are in general ineffective.
There remains a minority of patients who are resistant to treatment requiring trials of other therapeutic options. Topical potent corticosteroids have been used alone and as an adjunct to dapsone. Etretinate and more recently acitretin have been used as successful alternatives. Combination chemotherapy for myeloma has been associated with clinical improvement. Other therapeutic modalities anecdotally recommended include colchicine, ketoconazole, and minocycline.