Photosensitivity Episodes Related to Skin Color in People Treated With Dual‐Wavelength Low Power Laser Therapy: A Retrospective Cohort Study

Background/Purpose The therapeutic use of low‐level lasers aims to promote tissue photobiomodulation without raising the local temperature. However, in darker‐skin patients, melanin can increase temperature and cause adverse effects such as photosensitivity, especially in protocols with higher irradiances, such as those used in dual irradiations. Therefore, through a retrospective cohort, this project assesses the relationship between self‐reported skin color and the frequency of photosensitivity in patients treated with simultaneous dual irradiation protocols at the School of Dentistry of the University of São Paulo. Methods Data from patients treated with lasers between 2013 and 2023 were retrieved. Patients were divided into two groups based on skin color and assessed for photosensitivity after simultaneous irradiation with red and infrared wavelengths. Statistical analyses investigated the relationship between photosensitivity, skin color, patient characteristics, and delivered energy. Results Self‐reported skin color was associated with photosensitivity, with dark‐skinned patients having a three times higher risk of heating or thermal injury. The risk of clinically visible thermal injuries was nearly 12 times higher for this group compared to those with lighter skin. There was no correlation between the energy used and the degree of photosensitivity, nor was there a significant difference in energy between patients with and without photosensitivity. Conclusion Self‐reported skin color was associated with photosensitivity occurrence during simultaneous laser wavelengths irradiation. Further studies are needed to investigate the mechanisms underlying the relation between melanin and irradiance. Finally, individualized photobiomodulation protocols are needed to ensure patient safety and optimize the therapy's expected effects.