When You Can’t Make a Rash Diagnosis

For years, this 64-year-old man has complained of itching and a rash around his head and neck. He has consulted several primary care providers—and even a dermatologist. A punch biopsy performed by that provider yielded no clear diagnosis. The patient was advised to return for follow-up but never did so.

Treatment was attempted with a succession of medications; none resulted in any improvement. The list includes antifungal creams (econazole, clotrimazole, and miconazole), an oral antifungal medication (a one-month course of terbinafine 250 mg/d), and a corticosteroid (a one-month course of prednisone 20 mg/d).

In addition to the rash and pruritus, the patient feels “lumps” in the affected areas. He also reports feeling more tired than usual. Prior to the onset of these symptoms, his only complaint was lifelong eczema.

Large infiltrative plaques are seen on both sides of his neck, extending into his ears and onto his scalp. A few exceed 8 cm in diameter, and all have smooth surfaces with no epidermal disturbance. Several discrete, 2- to 4-cm, fixed nodules are also seen and felt on his neck below these plaques.

A 5-mm punch biopsy is performed on one of the plaques on his occipital scalp; the pathology report shows only chronic changes consistent with eczema. The decision is made to perform another biopsy. A deeper, wider, 5-cm wedge from the left preauricular plaque is taken and submitted. The report shows changes consistent with tumor-stage mycosis fungoides (MF).