Subcorneal pustular dermatosis and Sjögren's syndrome

Abstract

A 41‐year‐old Japanese woman presented at a local outpatient clinic because of a slightly pruritic pustular eruption on the trunk and extremities. Her skin lesion had been treated using an antifungal cream, but the condition had continued to worsen. According to the patient, the same pustular eruption had occurred during pregnancy, but diminished after delivery. She has no family history of skin eruption. On physical examination, she presented with well‐circumscribed erythematous macules with small pustules on the borders, involving the axilla, groin, upper and lower extremities and upper back (Fig. 1). Bacterial and fungal cultures of the lesions were negative. A skin biopsy obtained from a lesion in the left forearm demonstrated a subcorneal pustule containing polymorphonuclear leukocytes (Fig. 2). A perivascular dermal infiltrate was present, consisting predominantly of mononuclear cells. There was no spongiosis or acantholysis. On direct immunofluorescence, there were no immunoglobulin A (IgA) and complement 3 (C3) deposits in the intercellular space of the epidermis.Clinical appearance of the annular erythema with small pustules on the forearmimageSurgically excised specimen showing subcorneal pustules containing neutrophils and scattered eosinophils (hematoxylin and eosin; magnification ×200)imageThe clinical and histopathological findings were consistent with a diagnosis of subcorneal pustular dermatosis (SPD). Laboratory investigations showed hyper immunoglobulin A (IgA) immunoglobulinemia (479 mg/dL, normal, 110–410) and a high titer of antinuclear antigen (speckled type) at 1 : 160 (normal < 1 : 40) and anti‐single‐strand (anti‐ss) DNA‐IgG at 1 : 25 (normal : negative). Other findings were normal. Serum and urine immunoelectrophoresis showed no paraprotein bands. Administration of topical diflupredonate ointment and oral prednisolone improved but did not completely resolve the eruption. The patient was then treated with dapsone 75 mg daily, leading to reasonable control.Because speckled type antinuclear antibody and anti‐ss‐DNA antibody were positive in spite of the fact that autoantibodies anti‐Sjögren's syndrome (SS)‐A and SS‐B were negative, we asked the patient if she had experienced a dry sensation in her eyes and mouth. As she reported a dry sensation of both eyes and mouth, we referred her to the ophthalmology clinic. The Schilmer test was positive (2 mm of wetting per 5 min, with the patient unanesthetized). Rose Bengal dye and slit‐lamp examination revealed Sjögren's syndrome pattern. Lip biopsy revealed the accumulation of numerous lymphocytes in the salivary gland. Thus, our patient fulfilled four criteria of the European multicenter study,1 suggesting a diagnosis of definite Sjögren's syndrome.