Conventional photodynamic therapy (PDT) is an effective treatment for actinic keratoses (AK), however, tolerability is restricted by pain which almost invariably occurs during illumination. Cooling of the treated area is a widely used pain-alleviating method.

In this randomized controlled comparison study in patients with AK on the head region we compared the effects of a cold air blower (CAB) and fan (FAN) with respect to PDT-induced pain, skin temperature, phototoxicity and clearance rates.

Cooling with CAB resulted in greater pain relief and lower skin temperatures than cooling with FAN. PDT-induced phototoxicity and clearance rates were the same for both cooling methods.

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.

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.

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 °C vs. 32.1 ± 1.7 °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.

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.

Actinic keratosis

Photodynamic therapy

Pain

Cold air analgesia

Thermoreceptors

© 2022 The Authors. Published by Elsevier B.V.