Efficacy of Permanent Laser Hair Removal with a High-Power Diode Laser and Air-Cooling of the Skin: A Small Sample Size Study

The objective of laser hair removal is to damage the hair follicle as much as possible without affecting the skin. This is achieved with skin cooling systems (direct or indirect). Non-contact cooling methods, especially air-cooling, have been widely used in dermatological laser therapy. Objective: This study aims to present a laser-diode hair removal device with an accessory that allows the skin to be cooled by a stream of cold air without sacrificing the comfort, safety and efficacy of conventional contact-cooling treatments. Materials and methods: To compare the new air-cooling with conventional contact-cooling, a side-by-side study was performed on 16 subjects and 93 treatment areas with skin types ranging from II to V according to the Fitzpatrick classification. This comparison assessed the subjects' pain or discomfort using the VAS scale (0-10). To evaluate efficacy and safety, a proof of principle study was performed on 4 subjects and 20 treatment areas. Efficacy was evaluated according to hair reduction 3 months after one treatment. Static and dynamic modes were used. Results: Statistically significant differences were not found in the comparison between air-cooling and contact-cooling. Both cooling systems produced a similar and moderate level of pain, with a pricking sensation being the prevailing type of pain due to selective heating of the hair. Regarding the efficacy and safety study, a 43.4% (SD 23%) reduction was seen and no side effects were found to last more than 48 hours, with the results being classified as good to excellent for the treated subjects. Conclusions: A diode laser applicator in combination with the air-cooling accessory has accomplished the best balance between rapidity, efficacy, comfort and safety for the subject in hair removal treatments, with good results for hair reduction.