Leprosy mimics adult onset Still’s disease in a Chinese patient

Background: Leprosy is an infectious disease that mainly involves the skin and peripheral nerves. It is caused by acid-fast, rod-shaped bacillus Mycobacterium leprae. In recent time, it has become a major global health concern which requires an early diagnosis and proper treatment in order to avoid lifelong neuropathy and disability. It is considered a ‘great mimicker’ as it exhibits a similar clinical features that resembles many connective tissue disease.
Case presentation: We hereby describe a rare case of a 17-year-old-Chinese male referred to our hospital’s Rheumatology ward due to high grade fever of 40.3 °C, and painful erythematous nodules distributed over bilateral upper and lower limbs. He was previously misdiagnosed as adult onset Still’s disease (AOSD) and treated with immunosuppressive drugs. The diagnosis of borderline lepromatous leprosy with type-2 lepra reaction of was established on the basis of slit skin smear obtained from the lower right limb which showed few fragmented acid fast bacilli (AFB) by Ziehl-Neelsen staining. He was treated with multi drug therapy.
Conclusion: The prevalence of leprosy is highly variable; as vast majority of cases are found in developing countries across the globe. Mycobacterium leprae often presents in a rheumatology clinic with a vivid array of clinical manifestations that are similar to various rheumatic diseases and often confuses rheumatologists. Rheumatologists should be aware of leprosy to avoid errors in diagnosis and treatment.