CASE REPORT
A 50-year-old African-American woman presented to the dermatology clinic with a pruritic eruption of 3 years’ duration that began as discrete plaques on the inframammary folds and subsequently spread towards the mid-chest, ears, back, elbows, knees, and scalp. Past treatments by other clinicians included clotrimazole cream and a topical corticosteroid of unknown potency without significant improvement. She denied any new medications and was taking aspirin, divalproex, mirtazapine, cetirizine, venlafaxine, atorvastatin, and omeprazole.On clinical examination, the patient had well-demarcated, pink, atrophic plaques and superficial erosions over the inframammary folds and mid-chest (Figures 1). She also had well-demarcated, hyperpigmented, hyperkeratotic scaly plaques over the abdomen, suprapubic region, elbows, knees, and back with sporadic small superficial blisters (Figure 2). Complete blood count, complete metabolic panel, rheumatoid factor, and anti-nuclear antibody were within normal limits. Rapid plasma reagin test was negative. Erythrocyte sedimentation rate was elevated at 54 millimeter/hour (reference range 0-22 millimeter/hour). 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 (Figure 3). Only a sparse inflammatory infiltrate was present in the underlying dermis. These clinical and histological findings supported the diagnosis of pemphigus foliaceus (PF). Patient was started on 50 mg oral dapsone daily.
DISCUSSION
Herein, we present a case of PF with a psoriasiform clinical presentation in an African-American patient. PF is an autoimmune skin disease caused by antibodies against the desmosomal glycoprotein, desmoglein 1.1 Desmogleins, members of the cadherin family, serve to anchor epidermal desmosomes between adjacent keratinocytes and assist in epithelial differentiation.2 Antibodies targeting desmoglein 1 result in acantholysis in the upper epidermis with limited separation in the basal layers and minimal mucosal involvement as desmoglein 1 is primarily expressed in the granular layer of the non-mucosal epidermis.1 Patients present with scaly plaques on an erythematous base and fragile shallow blisters which are infrequently found intact; rarely, the condition can progress to exfoliative erythroderma.1,3 Initially, PF usually presents on the trunk, face, or scalp, but may subsequently involve other regions of the skin.1 Diagnosis may be confirmed with biopsy and direct immunofluorescence with intercellular IgG and C3 limited to the upper epidermis. Treatment includes oral and topical steroids, azathioprine, dapsone, and rituximab. The differential diagnosis for PF may include
