RESUMO
BACKGROUND: Solar lentigines are common, benign, cosmetically disfiguring lesions. Available physical treatments are effective, but they are costly and carry risks of side-effects. OBJECTIVE: To evaluate the efficacy and safety of a preparation containing undecylenoyl phenylalanine 2% in the topical treatment of solar lentigines. METHODS: In total, 36 patients with solar lentigines of the hands were randomly assigned to apply the active preparation on one side and the vehicle alone on the other side, twice daily for 12 weeks. Patients were evaluated monthly for efficacy and safety. RESULTS: In all, 30 patients (28 women and 2 men; age range 47-75 years) completed the study. The duration of lesions ranged from 8 months to > 10 years. All patients responded partially on the side of the active treatment. Of the partial responders, 19 (63.3%) had moderate improvement and 11 (36.6%) had marked improvement. Improvement was evident from the first follow-up visit. On the side of the vehicle, 26 remained stable (86.6%) and 4 (13.3%) had partial improvement. There was a significant difference (P < 0.01) in efficacy of the active preparation vs. the vehicle. Using patient assessment ratings, 80% were 'much more satisfied/more satisfied' with the result. The reported side-effects were minor and included erythema and itching or burning on the side of active treatment. CONCLUSIONS: Undecylenoyl phenylalanine 2% is a novel depigmenting agent, which possibly acts as an alpha-melanocyte-stimulating hormone antagonist, thus inhibiting melaninogenesis. It achieved a significant lightening of the lesions with minimal side-effects. Most patients were satisfied with the improvement. Undecylenoyl phenylalanine 2% may represent a safe, effective and inexpensive therapeutic alternative for solar lentigines.