Photographs here and below courtesy Gary Cole, MD
Subcorneal pustular dermatosis--also known as Sneddon-Wilkinson disease--is a chronic pustular dermatosis of unknown etiology. Women over 40 years of age are most commonly affected. IgA monoclonal gammopathy and myeloma have been associated. Some of these cases with an IgA paraprotein have been shown to have intercellular IgA on direct immunoflourescence. Obviously, IgA pemphigus must be excluded. Several patients have been described with both SPD and pyoderma gangrenosum both with and without a paraprotein.
Sterile superficial pustules develop with a preference for the trunk, axillae, and the flexor aspect of the limbs. Annular lesions occur. A hypopion-like effect with pus accumulating in the lower half of the pustule is characteristic. The lesions are thin-walled and fragile, and often rupture, leaving erosions. There are no systemic symptoms (in contrast for example to pustular psoriasis).
A DIF should be obtained (and found negative) to exclude IgA pemphigus. A bacterial culture should be done and found sterile. A serum protein electrophoresis should be done. The differential of widespread pustules may be consulted including pustular psoriasis.
Dapsone (e.g. 75-100 mg/day) or sulfapyridine are usually very effective. Long term therapy is usually needed. UVB, PUVA alone, PUVA plus dapsone [Dermatology 1999;198;203] and acitretin are alternatives.
This image from N Engl J Med 2012; 366:e31 shows blisters half filled with pus and the rest clear fluid in a patient with subcorneal pustular dermatosis/IgA pemphigus overlap.
Dermatology Online Journal 14(8)
J Am Acad Dermatology Volume 71, Issue 3, September 2014, Pages e85–e86
Homepage | FAQs | Contact Dr. White