RESUMO
BACKGROUND: We recently performed a pilot study which suggested that clinical and thermographic improvements occurred in patients with primary and secondary Raynaud's phenomenon (RP) following treatment with low level laser irradiation (LLLI). In view of these findings, we have proceeded with a double blind, placebo-controlled study. METHODS: Forty seven patients suffering from primary or secondary RP were randomly assigned in a double-blind manner to receive either 10 sessions of distant LLLI (16 f, 8 m, median age 45 years) or placebo irradiation (21 f, 2 m, median age 46 years) during winter months. The attack frequency of RP was measured by a diary count; its severity was assessed by means of visual analogue scale. Response to cold challenge test before and after LLL or placebo treatment was assessed by infrared thermography. RESULT: Overall a significant reduction of the frequency as well as the severity of RP in patients with either LLLI (frequency p < 0.0001, severity p < 0.0001) or placebo treatment (frequency p < 0.0001, severity p = 0.02) was found, but patients in the LLLI group exhibited a statistically more significant improvement of the frequency at 6 weeks p = 0.007 and 3 months p = 0.02 and the severity p = 0.02, p = 0.04 of RP. Thermographic response to cold challenge improved only in patients treated with LLL but not in those treated with placebo. CONCLUSION: LLLI significantly lowers the frequency and severity of Raynaud's attacks in patients with primary and secondary RP. Since this therapeutic modality is a safe, and non-invasive treatment, it might be considered as an alternative to existing therapeutic regimes.