Lepromatous leprosy presenting with chronic painless ulcers and inflammatory arthropathy: a case report from a...

Hansen's disease is a chronic infectious disease caused commonly by Mycobacterium leprae. Although it is rare in Europe, sporadic cases occur due to migration from endemic areas. In Portugal there are 4 cases reported in 2023 and 4 cases reported in 2024. Lepromatous leprosy represents the anergic pole of the disease spectrum, characterized by diffuse bacillary proliferation and multisystem involvement, often mimicking autoimmune conditions.

A 36-year-old Brazilian male from Rio de Janeiro living in Portugal presented with recurrent painless leg ulcers and violaceous halos for one year, accompanied by non-tender granulomatous lesions on the ears, eyelids, and nasal alas. He developed inflammatory polyarthralgias involving small and medium joints. Subsequent serologic and autoimmune studies revealed mild inflammatory activity, positive antinuclear antibodies and rheumatoid factor, elevated angiotensin-converting enzyme, and polyclonal hypergammaglobulinemia. Imaging demonstrated hepatomegaly and mild axillary and inguinal lymphadenopathy. Sarcoidosis was considered as the main differential diagnosis. Skin biopsy of an ulcer revealed foamy histiocytes and numerous acid-fast bacilli on Fite-Faraco staining, consistent with M. leprae. He was treated with multidrug therapy (rifampicin, clofazimine, and dapsone), leading to rapid resolution of lesions and arthralgias.

In an increasingly globalised world, even in non-endemic regions, leprosy should be considered in the differential diagnosis of chronic ulcers and inflammatory arthropathy, especially when patients come from endemic areas. An enhanced awareness among clinicians is needed. Early recognition, histopathologic confirmation, and multidrug therapy are essential to prevent irreversible complications and reduce transmission.