Skin cooling for botulinum toxin A injection in patients with focal axillary hyperhidrosis - A prospective, randomized, controlled study

Background: Botulinum toxin A (BTX-A) injections are a commonly used and effective therapy for patients with focal axillary hyperhidrosis. However, injections are often painful. Therefore, we studied whether skin cooling decreases pain during injection. Methods: Thirty-one patients (n = 31) with focal axillary hyperhidrosis were enrolled in the present study. Patients were treated with 50 MU BTX-A (Botox; Allergan, Irvine, CA) in each axilla. One group (n = 21) received a skin cooling using a cold-air system (SmartCool, Cynosure, Westford, MA) versus no cooling on the other side. In the second group (n = 10), patients were cooled with the same cold air blower on one axilla and ice cubes on the other. For evaluation of the effect of cooling in both groups, relative pain scores using a visual analog scale (VAS) were recorded. Results: In the first group, the air-cooled-side pain scores ranged from 0 to 4 (average: 2.5) versus 5 to 10 (average: 7.4) on the noncooled side. The air-cooled side showed a 66.2% higher reduction in pain score. In the second group, no significant difference was seen between air and ice cooling (average pain score 2.0 versus 2.4; P > 0.05). Conclusion: Skin cooling decreases pain during injection of BTX-A in patients with focal axillary hyperhidrosis, with ice and air cooling showing the same efficacy.