Chronic annular pustular psoriasis resembling subcorneal pustular dermatosis: A case report

Abstract

Generalized pustular psoriasis and subcorneal pustular dermatosis are generalized pustular dermatoses that are characterized by the subcorneal accumulation of neutrophils. Careful examination is important in distinguishing these diseases for appropriate management. Patients with acute generalized pustular psoriasis are systemically unwell with discrete pustules as opposed to the chronicity and associated hypopyon lesions in subcorneal pustular dermatosis. Generalized pustular psoriasis lesions demonstrate psoriasiform changes on histology and the increased expression of Th17 cytokines. We describe a middle-aged woman presenting with chronic annular generalized pustular psoriasis, initially mistaken for subcorneal pustular dermatosis due to their clinical and histological semblance. The patient had recurrent skin disease for 6 years despite conventional therapy of oral retinoid, immunosuppressant and biologic therapy. Complete and persistent clearance of her skin lesions was achieved with secukinumab, an interleukin 17A inhibitor.

Keywords: Sneddon–Wilkinson disease; Subcorneal pustular dermatosis; annular generalized pustular psoriasis; interleukin-17; secukinumab.

Figure 1.

Annular generalized pustular psoriasis: widespread pustular lesions over an erythematous base forming a circinate pattern. (a) Right upper arm, (b) forearms bilaterally, (c) trunk and (d) back.

Figure 2.

Histological examination of annular generalized pustular psoriasis: (a) H&E staining demonstrates classic psoriasiform changes of acanthosis, parakeratosis, subcorneal pustules, mild spongiosis and (b) histochemical staining demonstrates IL-17A in dermal infiltrates.