Efficacy of two different methods of cold air analgesia for pain relief in PDT of actinic keratoses of the head region - a randomized controlled comparison study

Background: Photodynamic therapy (PDT) is an effective method for treating actinic keratosis (AK) with pain during illumination representing the major side effect. The efficacy of two different cooling methods for pain relief in PDT of AK in the head region was compared. Methods: Randomized, assessor-blinded, half side comparison study in 20 patients with symmetrically distributed AK on the head. Conventional PDT was performed on both halves of the scalp or face by applying 20% aminolevulinic acid cream (ALA) and subsequent illumination with incoherent red light. During illumination one side was cooled with a cold air blower (CAB) and the other with a standard fan (FAN) in a randomized fashion. Pain and skin temperature were recorded during and after PDT. The phototoxic skin reaction was evaluated up to seven days after PDT. The clearance rate of AK was assessed at 3 and 6 months after PDT. Results: Mean pain (VASmean), maximum pain intensity (VASmax) and the mean skin temperature during PDT were significantly lower with CAB as compared to FAN (VASmean: 2.7 +/- 1.4 vs. 3.7 +/- 2.1, p = 0.003; VASmax: 3.8 +/- 2.0 vs. 4.8 +/- 2.5, p = 0.002; 26.8 +/- 2.0 degrees C vs. 32.1 +/- 1.7 degrees C; p=<0.001). The severity of the phototoxic skin reaction and the clearance rate of AK did not differ between the two cooling methods. Conclusion: Cooling with CAB during PDT has a greater analgesic effect than cooling with FAN. Patients with a lower skin temperature during illumination tended to experience less pain, however, this effect did not reach the level of statistical significance.

Automated summary

This study compared the efficacy of two different cooling methods, cold air blower (CAB) and standard fan (FAN), in relieving pain during photodynamic therapy (PDT) for actinic keratosis (AK) of the head region. The results showed that cooling with CAB had a greater analgesic effect and led to lower pain intensity and skin temperature compared to cooling with FAN. However, there was no significant difference in the severity of phototoxic skin reaction and the clearance rate of AK between the two cooling methods.