Subcorneal Pustular Dermatosis

Subcorneal pustular dermatosis is a rare, benign, chronic disease characterized by sterile pustular eruption, typically involving the flexural sites of the trunk and proximal extremities.

Epidemiology

Approximately 200 cases have been reported worldwide. The disease occurs more frequently in adults (40-60 years of age with a male to female ratio of 4:1).

Clinical description

Superficial flaccid grouped pustular lesions, which spread in an annular or gyrate pattern, arise within a few hours and resolve over a few days. Pruritus and irritation occur occasionally. The lesions characteristically evolve to fine scales with crusting and, in rare cases, mild hyperpigmentation. The disease may be associated with IgA monoclonal gammopathy, multiple myeloma or pyoderma gangrenosum. Less frequently associated conditions include rheumatoid arthritis, lupus erythematosus, hyperthyroidism and hypothyroidism, polycythemia rubra vera, SAPHO syndrome (see these terms).

Etiology

The etiology remains unknown.

Diagnostic methods

Diagnosis is confirmed by skin biopsy demonstrating a sterile subcorneal pustule filled with neutrophils, an absence of acantholysis, and negative results from immunofluorescence studies.

Differential diagnosis

Differential diagnosis includes the subcorneal-type of IgA pemphigus, pemphigus foliaceus, dermatitis herpetiformis, pustular psoriasis, generalized pustulosis, generalized exanthematous pustulosis and bacterial impetigo (see these terms).

Management and treatment

Management aims at preventing the complications. A dramatic response to dapsone has been reported but not all patients respond to this drug. Other possible treatments include sulfapyridine, oral corticosteroids, retinoids, colchicines and phototherapy.