Parapsoriasis with hyper-IgE.

A 56-year-old black man had generalized chronic dermatitis for two years before parapsoriasis en plaque (large type) with hyper-IgE (12,000-22,000 ng/ml) was diagnosed. Lymphocyte cultures showed decreased response to mitogens. Direct immunofluorescence of involved skin showed epidermal and dermal mast cells with bound IgE. Parapsoriasis with hyper-IgE may represent a form of "hypersensitive immunosurveillance" allowing a patient to reject a clone of malignant cells and retard transformation from a benign state (parapsoriasis) to a malignant state (mycosis fungoides).