Parapsoriasis in a 66-Year-Old Woman

The asymptomatic skin lesions seen on this 66-year-old woman had been present for 7 months. Therapy with topical and oral antifungal agents had failed. The annular patches were pale to bright red and very slightly scaly; they affected the lower third of the patient's back and abdomen and her flanks, buttocks, and upper thighs. Examination of a skin biopsy specimen confirmed the suspicion of parapsoriasis en plaques, also known as large plaque or premycotic parapsoriasis.

Although the annular nature of this eruption suggested a dermatophytosis, the disorder is often a precursor to cutaneous T-cell lymphoma (mycosis fungoides). The lack of pruritus is typical, as is the location. The patient's lesions cleared completely after 4 months of psoralen plus UVA therapy. Had phototherapy failed, treatment with topical nitrogen mustard (aqueous or ointment) would have been given. This case will be followed closely for signs of recurrence, writes Dr Ted Rosen of Houston.