Indeterminate leprosy: case report and literature review

Background:

 The World Health Organization (WHO) states that Morbus Hansen (MH) or leprosy is one of seventeen neglected tropical diseases that require special global attention. Individuals infected with leprosy but who have not yet developed a cell-mediated immune response to the organism are classified as indeterminate type. If left untreated, an indeterminate type of leprosy can develop into the tuberculoid or lepromatous type. This case report aims to provide a clinical description of the indeterminate type of leprosy, to increase understanding and awareness of this condition.

Case:

 A 25-year-old man presented with white patches and numbness on his back for the past year, with a history of being diagnosed with leprosy at the age of 12 and completing leprosy therapy. Physical examination revealed multiple macular patches with decreased sensitivity, without peripheral nerve thickening. Slit skin smear examination found no acid-fast bacteria (AFB). Histopathological examination with Ziehl-Neelsen staining found the epidermis covered by weavy keratin and perivascular lymphohistiocytic patterns, partly following the neurovascular pathway in the superficial part, without finding any AFB. A diagnosis of indeterminate-type leprosy was established with multidrug therapy (MDT) of the paucibacillary (PB) type. Improvement in sensitivity without skin complications was noted after completing treatment.

Conclusion: 

Early detection and appropriate treatment of leprosy are essential to reduce transmission of M. leprae to close family members, especially household contacts. Continuous therapy and regular monitoring are crucial to improve treatment success.