Cold water and pauses in illumination reduces pain during photodynamic therapy: a randomized clinical study

Pain is the main acute adverse event during photodynamic therapy of skin lesions. The objective of this randomized study was to evaluate the pain-relieving effect of pauses and cooling during illumination. Twenty-four patients with actinic keratoses were treated with photodynamic therapy in two symmetrical areas and cooled with either cold-water-spray or cold-water-pack (CoolPack). Treatment areas were cooled during either the first or second period of illumination, which were separated by a 3-min pause in illumination. Pain intensity was scored from 0 to 10. Water-spray reduced the mean pain score by 1.2 points (p=0.030) and CoolPack by 1.3 points (p=0.007) during the first half of the illumination. Pain intensity decreased during the pause by 3.7 points in water-spray patients (p<0.0001) and 3.0 points in CoolPack patients (p<0.0001). In conclusion, cooling resulted in a minor reduction in pain intensity, while adding the intermediate pause in illumination reduced the pain considerably. Use of pauses and cooling during illumination is an easy and inexpensive way to make photodynamic therapy more tolerable for the patient.