A case of persistent psoriasis occurring after influenza vaccination

Abstract

Sir, A thirty-year-old male received influenza vaccination in the upper arm. Several days later, erythema appeared on the vaccinated site and spread to the trunk and extremities. He had no family history of psoriasis. He was treated with a topical corticosteroid for three months, which yielded no effects and, thus, he was referred to our hospital. A physical examination revealed numerous erythematous, scaly macules scattered on the trunk and upper extremities and erythema with thick scales scattered on the lower extremities (Figs. 1a and 1b). The psoriasis area and severity index (PASI) score was 9.7. We performed a skin biopsy from the left lower leg. Histopathology revealed a regularly elongated epidermis, an absent granular cell layer of the epidermis, parakeratosis in the corneal layer, and subcorneal neutrophil infiltration (Fig. 1c). Immunohistochemistry revealed that CD4- and CD8-positive T-cells infiltrated into the epidermis and upper dermis, and IL-17, CD123, and TNF-a were also detected in the inflammatory cells below the epidermis. He was diagnosed with psoriasis and was started on a treatment with topical betamethasone and calcipotriol formula (Dovobet) ointment and oral cyclosporine (300 mg/day). An improvement in the skin lesions other than those in the lower extremities was observed after two months. However, the scaly, erythematous lesions on the lower legs were resistant to therapy. The treatment was continued thereafter.