Recurrent Pruritic Erythematous and Pigmented Plaques

A 37-year-old woman presented to a dermatology clinic for evaluation of recurrent, pruritic, inflamed plaques on her neck, thigh, back, and shoulder.

History. The lesions had flared at irregular sporadic intervals over the past year and resolved with hyperpigmentation (Figures 1 and 2). The patient’s history was notable for atopic dermatitis, bilateral pulmonary embolism, and a 3-year history of recurrent candida infections, with the most recent infection occurring 2 months prior to presentation. The patient reported using triamcinolone 0.1% cream as needed for her atopic dermatitis and topical clotrimazole 2% cream for 3 nights when needed for vaginal candidiasis.

Empiric therapy with hydrocortisone cream 2.5% applied twice daily for 2 months was ineffective in resolving the hyperpigmentation. Her family history was remarkable for her mother, father, and sister all having sarcoidosis. She denied any allergies or exposure to any allergens. She did not associate the skin findings with any of her medications or over the counter substances. She was otherwise in good health. 

Figure 1. Hyperpigmented area on the patient’s anterior neck.

Figure 2. Hyperpigmented plaque on the patient’s thigh.

Diagnostic testing. Biopsies of the thigh for routine histology and direct immunofluorescence were performed at the time of the office visit. Necrotic keratinocytes, eosinophils, and melanophages were noted (Figures 3 & 4) in the biopsy results. The inflammation was distributed along the dermal-epidermal junction, but no blisters were encountered. No granulomas were identified and the biopsy for direct immunofluorescence failed to reveal deposition of immunoreactants along the dermal-epidermal junction or in any other location.

Figure 3. Biopsy reveals necrotic keratinocytes and an inflammatory infiltrate with numerous melanophages (hematoxylin and eosin-stained sections, original magnification 100x).