Cutaneous Nocardiosis in the Very Elderly: A Case of Lymphocutaneous Infection and a Literature Review of Patients Aged Over 85 Years.

Cutaneous nocardiosis is an uncommon but clinically significant opportunistic infection, primarily affecting immunocompromised individuals, including those with underlying malignancies, organ transplants, or chronic corticosteroid use. Although it can also occur in elderly patients, this is often due to age-associated immunosenescence or comorbid conditions that impair immune function. We describe a case of lymphocutaneous infection in an 87-year-old man with no history of trauma or corticosteroid use. The patient had been receiving long-term low-dose methotrexate (MTX) for rheumatoid arthritis. He presented with painful, erythematous nodules arranged along the lymphatic vessels of the right forearm. Histopathological analysis and culture confirmed the diagnosis. Oral trimethoprim-sulfamethoxazole (TMP-SMX) and minocycline were initiated; minocycline was discontinued after three weeks due to gastrointestinal symptoms. MTX was also stopped in response to clinical progression. The lesions resolved completely with continued TMP-SMX monotherapy over a three-month course. A brief review of the literature revealed only a few reported cases of cutaneous nocardiosis in individuals over 85 years of age. Some of these lacked clear immunosuppressive backgrounds or trauma history. While TMP-SMX remains the standard therapy, its use in older adults may be constrained by tolerability. This case serves as a reminder that infection should be considered in the differential diagnosis of nodular skin lesions in very elderly patients, even in the absence of typical risk factors.