To cite this article: Schoenewolf NL, Hafner J, Dummer R, Bogdan Allemann I. Laser treatment of solar lentigines on dorsum of hands: QS Ruby laser versus ablative CO 2 fractional laser -a randomized controlled trial. Eur J Dermatol 2015; 25(2): 122-6Background: Lentigines solares (LS) on the dorsum of hands are often esthetically disturbing. Q-switched ruby laser treatment is highly effective in the treatment of these lesions. Ablative fractional photothermolysis may be a suitable alternative. We compared the Q-switched ruby laser with ablative CO 2 fractional photothermolysis for the treatment of solar lentigines. Objective: To evaluate the efficacy and side-effects of 694nm Q-switched ruby laser (Sinon) with the ablative 10,600nm CO 2 fractional laser (Quantel Excel O2) in an intra-individual side-to-side comparison in the treatment of LS on the dorsum of hands. Material and methods: Eleven patients were included in the study. The hands of each patient were randomized for treatment with the two laser systems. Three treatment sessions were scheduled at weeks 0, 4 and 8. Evaluations by patients, treating physician and blinded experts were scheduled at weeks 0, 4, 8, 16 and 24. Results: The Q-switched ruby laser was significantly more efficacious than the ablative CO 2 fractional laser for removing LS on the dorsum of hands (p = 0.01). Conclusion: In this first study on this topic, the Q-switched ruby laser was superior to the ablative CO 2 fractional laser in the treatment of lentigines solares on the dorsum of hands.