Objective: To investigate the effect of cold air cooling on the incidence of postinflammatory hyperpigmentation (PIH) after laser treatment in Asian patients.
Design: Randomized, controlled, split-face study.
Setting: Skin laser center of a university hospital.
Patients: Twenty-three Thai women with acquired bilateral nevus of Ota-like macules.
Interventions: Patients were treated using a 1064-nm Q-switched Nd:YAG laser at an average fluence of 7.0 J/cm(2) using a 3-mm spot size. The same laser fluence was used on both sides of the face in individual patients. One randomly selected face side of each patient was cooled using a cold air cooling device during and 30 seconds before and after laser irradiation, and the other side was irradiated without cooling.
Main outcome measures: Occurrence of PIH was objectively evaluated by measuring the melanin index using a spectrometer, and it was subjectively assessed by 2 nontreating physicians before treatment and once weekly for 4 weeks.
Results: Of the 21 patients who completed the study, 13 (62%) and 5 (24%) developed PIH on the cooled and uncooled sides, respectively. One patient (5%) had PIH on both the cooled and uncooled sides, and 2 (10%) did not experience PIH. The cooled sides were significantly more likely to become hyperpigmented after laser irradiation than the uncooled sides (relative risk, 2.6; 95% confidence interval, 1.13-6.00; P = .03). The clinical evaluation corresponded to the spectrometer reading.
Conclusion: Epidermal cooling with cold air is associated with an increased risk of PIH after Q-switched Nd:YAG laser treatment.
Trial registration: clinicaltrials.gov Identifier: NCT00287001.