Use of Topical Coal Tar Foam for the Treatment of Psoriasis in Difficult-to-treat Areas.

Psoriasis in some body parts can be challenging to treat. Psoriasis in the scalp, palms and soles, and intertriginous areas differ from disease on other body parts, and treatment regimens must be tailored to these areas. The presence of hair, along with the frequent, thick scale of psoriasis makes the scalp a challenge to treat. Skin in the body's intertriginous areas is often thin, limiting treatment options for inverse psoriasis. Finally, palmoplantar psoriasis is often resistant to topical therapies because of the thickness of the skin. Moreover, cosmetic acceptibilty of a topical medicine is important when treating these areas. Coal tar has been used to treat psoriasis for hundreds of years. In a novel foam vehicle, coal tar 2% is versatile and may be used to treat psoriasis even in challenging areas of the body, such as the scalp, intertriginous areas, and palms and soles.