Treatment of intractable pruritus ani.

The majority of patients with idiopathic pruritus ani respond favorably to conservative treatment. Moreover, response to specific medical therapy is almost always favorable in certain dermatologic diseases such as psoriasis, mycotic dermatitis, and contact dermatitis. When surgery is performed for anorectal disorders such as hemorrhoids and fistulas, or potentially malignant entities such as extramammary Paget's disease, the accompanying pruritus ani invariably improves as well. Only patients with chronic intractable pruritus ani are included in the current study. Methylene blue (methylthionine chloride) 0.5 percent is injected intracutaneously on the anodermal and perianal skin. With one treatment, long-term cure has been observed.