Does hair removal necessary after crystallized phenol treatment in pilonidal disease?

Objective: The most important cause of post-treatment recurrence in the pilonidal sinus is the re-entry of hair into the skin. The study aimed to investigate the effect of hair removal and its duration on the prevention of recurrences after crystallized phenol treatment. Subject and Methods: The patients with pilonidal sinus disease who were treated with crystallized phenol treatment were evaluated. Hair in the sacrococcygeal area were removed with depilatory cream before every crystallized phenol procedure, during the treatment, and after treatment once a month for six years. Of 1016 patients, 735 were contacted by telephone or e-mail regarding the frequency of sacrococcygeal hair removal and recurrence. Demographic and sinus features and crystallized phenol application data of patients treated with crystallized phenol for pilonidal sinus disease, as well as recurrences were retrospectively assessed. Results: The mean follow-up time was 46.23 ± 33 (range, 11–240) months, with 139 (18.9%) patients experiencing recurrence. Patients who underwent hair removal experienced significantly less recurrence than those who did not (p = 0.003, odds ratio (OR): 0.54 [0.36–0.82]). The OR of recurrence decreased by 0.8% every month as the hair removal time increased (OR = 0.992, 95% CI = 0.985-1.000, p = 0.049). The cut-off value for sensitivity was 0.636, specificity 0.466, and area under the curve 0.562 in hair removal procedures that lasted for over 30 months. Conclusion: Regular hair removal during and at least 30 months after crystallized phenol treatment reduced recurrences in patients with pilonidal sinus disease.