Affection of immune zones in leprosy: a clinico-epidemiological study

The study was undertaken to evaluate the prevalence of involvement of immune zones in leprosy and to assess the clinico-epidemiological characteristics of the disease in patients presenting with immune zone involvement. 200 leprosy cases were included in this study and detailed history, clinical examination, slit-skin smears and skin biopsies were carried out on all patients. Those cases presenting with immune zone involvement were further evaluated for clinical and epidemiological characteristics of disease process. Immune zone involvement was detected in 7% of cases with male preponderance in the study. Majority of patients (85.5%) had borderline tuberculoid leprosy and midline of back was the commonest site of involvement (50% of cases). Morphologically, macular lesions were the commonest presentation (85.68%) of immune zone involvement. The study heightens the clinical awareness of the possibility of occurrence of leprous lesions on uncommon and unusual sites, which should be termed as relatively immune, rather than absolutely immune zones of leprosy.