Itching in acne--an unusual complication of therapy.

Pruritus at the site of active acne has not been described before as a complication of acne therapy. We report 8 cases seen over a 3-year period at our department with localized itching mainly at the active acne sites, within 2-6 weeks of starting effective acne therapy. Seven had oral tetracyclines (oxytetracycline, Vibramycin or Minocin) with or without topical antibiotics or benzoyl peroxide. Only 1 patient received oral isotretinoin. The severity of itch was mild to moderate in most cases with the severest reaction in the isotretinoin-treated patient. All cases resolved within 4 weeks, 7 with non-sedative antihistamine therapy (terfenadine), and 1 resolved spontaneously upon cessation of antibiotic therapy. The pathogenesis of this localized itch is presumed to be related to the change in pH of the micro-environment of the acne follicle providing an optimal environment for the production of histamine or histamine-like products by Propionibacterium acnes. This report highlights the self-limiting nature of pruritus during effective anti-acne therapy. Increased awareness of this uncommon complication helps prevent the unnecessary discontinuation of effective acne therapy.