Background
Cognitive Behavioral Therapy (CBT) is an effective treatment for Skin Picking Disorder (SPD). However, since individuals have limited access to CBT, telepsychotherapy can overcome this barrier.

Objective
Evaluate the efficacy of a self-guided digital CBT intervention for SPD.

Methods
This controlled clinical trial randomized 163 patients with SPD to receive 4 weeks of online CBT (SOSkin) or a control intervention (videos about quality of life). Primary outcome was the improvement in the Skin Picking Scale-Revised (SPS-R) and secondary outcomes were the improvement in Dermatology Life Quality Index Scale (DLQI), Generalized Anxiety Disorder Assessment Scale (GAD-7), and Patient Health Questionnaire-9 Scale (PHQ-9).  Instruments were applied at baseline, middle and end of intervention and at 1 and 3 months of follow up. SOSkin usability was evaluated using the System Usability Scale (SUS). Data were analyzed using the Generalized Estimating Equations model (GEE).

Conclusion
There was no difference between groups in completion rates. SOSkin has excellent usability. Both groups improved the SPS-R and the DLQI scores after treatment and at the follow-up assessments. We found a significant time*group interaction in favor of CBT on SPS-R. Effect size of the intervention compared to control over SPS-R was small after treatment and at the follow-ups; over the DLQI was moderate after treatment and small at the follow-ups. CBT was superior to control on SPS-R when we compared the percentage of change from baseline. CBT was superior to control condition over DLQI at the end of treatment and at 1 month follow-up.

Clinical Trials Registration: NCT04731389.