Subcorneal pustular dermatosis with vesiculo‐bullous eruption. Demonstration of subcorneal IgA deposits and a leukocyte chemotactic factor

We report an unusual case of subcorneal pustular dermatosis with widespread vesiculobullous lesions. Reduction of the oral prednisone dosage provoked a severe exacerbation, with erythroderma associated with massive pustule formation. This was effectively controlled by topical PUVA. Subsequent recurrence of skin lesions responded well to oral etretinate. Investigation revealed intercellular IgA deposits at the upper epidermis of the paralesional skin, but no circulating antibodies were detected. Characterization of the chemotactic activity of the soluble components of the scales revealed the presence of a 12,000 molecular weight leukotactic factor resembling that found in psoriasis. Furthermore, the vesicle fluid showed only this chemotactic factor, indicating that it may be a major factor in the pathogenesis of subcorneal pustules.