Psoriasiform Pemphigus Foliaceus in an African American Female: An Important Clinical Manifestation.

A 50-year-old African-American woman presented to the dermatology clinic with a pruritic eruption of 3 years' duration. On clinical examination, the patient had well-demarcated, pink, atrophic plaques and superficial erosions over the inframammary folds and mid-chest. She also had well-demarcated, hyperpigmented, hyperkeratotic scaly plaques over the abdomen, suprapubic region, elbows, knees, and back with sporadic small superficial blisters. A punch biopsy of the right abdomen was performed and revealed psoriasiform epidermal hyperplasia, focal parakeratosis, and acantholysis throughout the superficial spinous and granular layers. Only a sparse inflammatory infiltrate was present in the underlying dermis. Clinical and histological findings supported the diagnosis of pemphigus foliaceus (PF), but psoriasis was included in the differential diagnosis due to the presence of discrete plaques with an erythematous border. We hypothesize that patients with psoriasiform presentations of PF may be misdiagnosed with plaque psoriasis. It is important to distinguish between PF and psoriasis as there is evidence that ultraviolet light, a common treatment for psoriasis, may exacerbate PF. We document and highlight this atypical psoriasiform presentation of PF in a patient with skin of color to raise awareness and improve diagnosis and outcomes. <p><em>J Drugs Dermatol. 2018;17(4):471-473.</em></p>.