Scabies associated with radiation therapy for cutaneous T-cell lymphoma.

Scabies, infection with Sarcoptes scabiei, is known to be predisposed to by poor body hygiene, environmental exposure, and systemic immunodeficiency. We report the case of an 83-year-old man with Sezary's syndrome who developed scabies limited to the skin of the upper chest, the same location where he had previously received electron beam radiation treatments for cutaneous T-cell lymphoma. Histologic and immunohistochemical studies demonstrated that sections of the previously irradiated right and left chest skin, compared to non-irradiated chest, abdominal, and leg skin, had infestation by scabies, diminished involvement by T-cell lymphoma, and notably reduced numbers of Langerhans cells. These findings suggest that the development of scabies may be predisposed to by local cutaneous radiation therapy, and that it may be mediated by local cutaneous immunodeficiency secondary to reduced numbers of Langerhans cells.