The efficacy of macrolides and acyclovir in pityriasis rosea.

Sir, We read with interest the article by Pandhi et al.,[1] who evaluated the efficacy of azithromycin in pityriasis rosea (PR) and we are not entirely surprised by its failure. In fact, an increasing number of studies using valid methodology have focused on the role of systemic infection with human herpes virus (HHV) 6 and/or 7 as the cause of pityriasis rosea.[2] Hence, azithromycin had only a slight chance to show any efficacy, unless it was due to its modest anti‐inflammatory and immunomodulatory properties. As a viral disease, instead, pityriasis rosea could be responsive to antiviral drugs and, in fact, we obtained a fast response in 87 consecutive patients treated with high‐dose oral acyclovir, 800 mg given 5 times daily for 7 days.[3] Thirty percent of patients had complete regression of lesions and over 60% had partial regression within one week. In addition, in the treated patients, significantly fewer new lesions appeared than in the placebo group and the systemic symptoms were alleviated as well. The response was surprising since it was obtained after only 1 week, considering that, in most studies on the systemic treatment for pityriasis rosea, the effect was evaluated after 2 weeks, a time at which the disease is already undergoing spontaneous remission in a number of patients.