Seasonal patterns of idiopathic facial paralysis: a 16-year study.

The annual frequency of Bell's palsy in 16 consecutive years was investigated in a 465,000-person health area in Madrid, Spain. The annual incidence of Bell's palsy per 100,000 population was found to be 24.1. The male-to-female ratio was 46:54. Seasonal difference in the incidence was noted in our series with fewer cases during summer. According to these results, the illness in Spain seems to have a similar incidence to that in Western countries. In addition to this, Bell's palsy does not have an infectious epidemiologic pattern in our country, but its frequency decreases in warm weather.