Cold air analgesia as pain reduction during photodynamic therapy of actinic keratoses

Background Photodynamic therapy (PDT) is an effective treatment for actinic keratoses and non-melanoma skin cancer. The main side effect of PDT is pain during the illumination. Objectives To assess the effect of cold air as pain relief during MAL-PDT for field cancerization on different body areas. Methods A prospective, open, intra-individual right-left comparison study was performed in 43 patients with MAL-PDT as field cancerization. One area received cold air analgesia while the other did not. Pain was evaluated by numeric rating scale (NRS) during the illumination. The patients received a questionnaire and recorded pain and postinflammatory symptoms on a visual analogue scale (VAS). Results We found a statistical significant difference in overall pain score at 3 and 9 minutes. The area receiving cold air during illumination had a mean NRS of 5.1 while the opposite side, not receiving cold air, had NRS of 6.1. At 9 minutes the side receiving cold air had mean NRS of 5.0, and the side without had 5.7. The pain difference on the chest was the most pronounced with a NRS of 5.2 without air and 3.5 with cold air. There was a significant difference in erythema immediately after, 1 h and 24 h after illumination. Limitations Small, open, not blinded study. The difference in pain was small. Conclusion Cold air is an effective method for moderate pain relief. It is an easy, noninvasive method that can be used on all body parts.