Risk factors for recurrence after successful treatment of warts: the role of smoking habits

Several therapies have been proposed for cutaneous warts without results concerning factors affecting recurrences.

To determine the importance of individual characteristics and different therapy modalities in the occurrence of relapses.

Observational prospective cohort study including 199 patients affected by multiple plantar warts treated as follows: 49 with keratolytics, 50 with CO₂ laser, 50 with pulsed dye laser (PDL) and 50 with cryotherapy. Personal data were evaluated through a questionnaire, and treatment information was collected. A Cox regression analysis was performed to identify independent factors for relapse occurrence.

Of patients, 57.8% showed a persistent clearance of warts after treatment with a higher recurrence-free interval when treated with PDL. Accordingly, the risk of recurrence was increased with CO₂ laser [hazard ratio (HR) 2.92, 95% confidence interval (CI) 1.49-5.74] and keratolytic treatment (HR 3.23, 95% CI 1.60-6.54), as compared to PDL. Furthermore, the multivariate analysis highlighted a higher risk of recurrence in patients between 26 and 35 years (HR 1.88, 95% CI 1.03-3.45), older than 35 (HR 2.23, 95% CI 1.23-4.07) and smokers (HR 4.90, 95% CI 3.09-7.78).

Pulsed dye laser is characterized by the lowest rate of recurrence. Furthermore, our study highlights that the risk of warts relapse is 5-fold higher in smokers compared to non-smokers, revealing the importance of the effects of smoking on inflammation and immune response.