Efficacy of erythromycin for psoriasis vulgaris

Psoriasis is characterised by the presence of neutrophil overactivation and overproduction of interleukin (IL)-6 and IL-8 from keratinocytes. It is now clear that macrolide antibiotics have anti-inflammatory effects, such as inhibition of IL-6, IL-8 and tumour necrosis factor-alpha, perhaps by suppressing the transcription factor nuclear factor-kappaB or activator protein-1, and reduction of neutrophil activity. It is thus possible that macrolides might be a candidate for adjunctive treatment of psoriasis. In this study, we investigated the effectiveness of treatment with the macrolide antibiotic, erythromycin, for skin lesions and pruritus of patients with psoriasis. In total, 60 patients with psoriasis, especially pruritic psoriasis, were included. This was an open-label study and the analysis was on an intention-to-treat basis. Oral macrolide antibiotics and topical corticosteroids were given to the study group of 36 patients. The control group (24 patients) were treated only with topical corticosteroids. After a 4-week treatment period, scores on the Psoriasis Area and Severity Index (PASI) at baseline and at the end of the treatment, and the effectiveness in reducing itching were compared within and between both groups. Although there was no statistically significant difference between the baseline mean PASI of the two groups (P=0.81), there was a statistically significant difference between the mean PASI of the two groups at the end of the treatment (P=0.023, 95% confidence interval: - 3.45 to - 0.27). The comparison of the mean difference in PASI yielded a statistically significant difference (P=0.03, 95% confidence interval 0.73-3.55). Our study suggests that macrolides could be used as one of the adjunctive therapies for psoriasis vulgaris.