Epidemiological significance of first skin lesion in leprosy

The epidemiological significance of monolesions in leprosy and the possible inferences on the mode of entry by Mycobacterium leprae into the body are presented based on data from the clinical records of the Leprosy Control Programme of Gudiyatham Taluk in India; 660 children with monolesions (335 males, 305 females) younger than 15 years of age and detected during the period 1990-1995 were included in the study. Detailed investigations on the location of monolesions were carried out and compared with a random sample of 669 normal rural children matched for age and sex. A large majority of the leprosy monolesions were in the uncovered parts of the body, with special predilection for the posterior aspects of the upper extremities and the anterior aspects of the lower extremities. Based on observation of normal children, these happen to be precisely the sites vulnerable for trauma since they are exposed to the environment where M. Leprae could enter through abraded skin and manifest as a patch. The need for further studies is emphasized.