Selection of sites for slit skin smears in untreated and treated leprosy patients.

A total of 1000 slit-skin smears were taken from multiple sites (both ear lobules, right elbow, dorsal aspect of middle phalanx of the left finger, and dorsum of middle phalanx of the right foot) from 558 leprosy patients. There were 319 sets (1595 smears) from untreated patients and 681 sets (3405 smears) from the treated group. The duration of treatment varied from 6 months (multidrug therapy) to 7 years (dapsone monotherapy). The ear lobules gave significantly higher values for the bacterial index (BI) compared to toes and fingers in the untreated group. The morphological index (MI) was also significantly higher from the ear lobules compared to toes, elbows, and fingers. In five patients from the untreated group, bacilli were found in some other sites when the earlobes did not reveal any. In the treated group, all sites yielded similar BI and MI values, the figures being lowest from elbows and toes but not different statistically. In 20 long-treated patients, bacilli were detected at sites other than the ear lobules. In 28 patients, sites other than the ear lobules gave a higher MI and in 20 patients, solid bacilli were seen at sites other than the ear lobules.