A clinical study of the involvement of cranial nerves in leprosy.

A clinical descriptive study was conducted to assess the frequency and pattern of involvement of cranial nerves in leprosy and to study the relationship of cranial nerve involvement with a leprosy patch or patches on facial skin. One hundred consecutive patients of leprosy, diagnosed by clinical features and/or slit skin smear and histopathology, were studied; of these, 22 patients had cranial nerve involvement. The mean age of patients with cranial nerve involvement was 41.2 years. 16 patients (72.7%) with cranial nerve involvement were in the age-group of 20-49 years. The male-to-female ratio was 3.4:1. The mean duration of the disease in these patients was 5.73 years. The duration of the disease in the majority of patients with cranial nerve involvement was less than 5 years. Impairment of cranial nerves was seen in 12 BT patients, 6 BL patients, and 4 LL patients. No significant difference was noted between involvement of cranial nerves in PB and MB patients. Among the cranial nerves, facial nerve was the most common nerve involved (10/22), followed by olfactory (9/22), trigeminal (7/22) and auditory (3/22) nerves. Among the risk factors, it was found that facial nerve impairment was significantly associated with facial patch(es) and also type 1 lepra reaction.