The efficacy of macrolides and acyclovir in pityriasis rosea

Francesco Drago, Giulia Ciccarese, Alfredo Rebora, Aurora Parodi

 IRCCS A.O.U. San Martino IST DISSAL, Department of Dermatology, Largo Rosanna Benzi 10, Genoa, 16132, Italy

Correspondence Address:
Giulia Ciccarese
IRCCS A.O.U. San Martino IST. DISSAL, Department of Dermatology, Largo Rosanna Benzi 10, Genoa, 16132 Italy
Italy

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.

Furthermore, the authors cited neither the paper by Ehsani et al. ^[4] who compared erythromycin (400 mg 4 times a day for 10 days) with acyclovir (4 g daily for 10 days) and confirmed that the latter is more effective, nor the recent paper by Amatya et al. ^[5] who repeated the study and drew the same conclusions.

At the moment, no treatment can be recommended on the basis of evidence-based medicine and pityriasis rosea remains a self-limiting exanthematous disease that probably needs just reassurance and a little rest. However, it should not be forgotten that a safe treatment for pityriasis rosea in pregnancy is yet to be found., ^[2] In fact, when occurring in pregnant women, pityriasis rosea may herald a possible HHV-6 and/or HHV-7 intrauterine fetal infection with premature delivery and even fetal death. ^[2] This is especially true when pityriasis rosea develops during the first weeks of gestation, the lesions have an unusual extension and long duration, and constitutional symptoms are present. In such cases of pityriasis rosea, which might affect the outcome of pregnancy, appropriate antiviral therapy may be considered.

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