Decade-Long ‘Eczema’ on Hand Unmasked as Rare Cutaneous Tuberculosis: Case Report
USA: A rare case of cutaneous tuberculosis (CTB) masquerading as a chronic dermatologic condition has highlighted the diagnostic complexity of this uncommon form of extrapulmonary tuberculosis.
The case, published in Case Reports in Dermatological Medicine by Olivia Spina from Cooper Medical School of Rowan University, Camden, New Jersey, USA, and colleagues, highlights the importance of clinical vigilance and individualized treatment strategies.
CTB represents an infrequent manifestation of tuberculosis and can resemble a range of inflammatory or infectious skin disorders. One particular subtype, tuberculosis verrucosa cutis (TBVC), poses additional challenges because it typically contains a low bacterial load. As a result, routine laboratory methods such as acid-fast bacilli staining, culture, and polymerase chain reaction (PCR) testing often fail to detect the organism.
The report describes a 73-year-old woman with a 10-year history of recurring lesions on her left hand. Born in Japan and residing in the United States since early childhood, she had no known history of tuberculosis exposure, prior infection, or recent travel. Her medical background included prediabetes, hyperlipidemia, and hypertension. Decades earlier, she had tested negative on a tuberculin skin test.
The lesion initially developed after a minor trauma from a blood lancet injury to her left index finger. Over time, intermittent swelling and small papules evolved into a persistent, scaly, thickened eruption involving the second and third digits and extending across the dorsal hand. Initially diagnosed as eczema, the condition worsened with topical corticosteroid therapy, prompting reconsideration of the diagnosis.
A skin biopsy revealed suppurative granulomatous dermatitis, raising suspicion for an infectious cause. However, special stains and microbiological testing for mycobacteria and fungi were negative. Despite these inconclusive findings, a QuantiFERON-TB Gold interferon-gamma release assay (IGRA) returned strongly positive, supporting the diagnosis of tuberculosis verrucosa cutis. The patient was referred to infectious disease specialists for management.
Standard first-line antituberculosis therapy—isoniazid, rifampin, pyrazinamide, and pyridoxine—was initiated under directly observed treatment. Within 10 days, the patient developed muscle aches, fatigue, appetite loss, weight loss, and a pruritic rash. Pyrazinamide was discontinued first, but symptoms worsened, necessitating temporary cessation of all medications. After symptomatic management, isoniazid was successfully restarted. Rifampin rechallenge led to severe myalgias and was permanently discontinued.
The patient was transitioned to an alternative regimen consisting of ethambutol, isoniazid, levofloxacin, and pyridoxine. She tolerated this combination well, and within a month, the lesion began to flatten and heal. After completing eight months of therapy, her skin findings had resolved significantly, and treatment was concluded.
The authors emphasize that TBVC can mimic common dermatologic disorders, leading to prolonged misdiagnosis. In paucibacillary cases, interferon-gamma release assays may provide crucial diagnostic support when conventional tests are negative. The case also illustrates the need for close monitoring of drug-related adverse effects and flexibility in tailoring treatment regimens. Early recognition and individualized care remain essential to achieving favorable outcomes in cutaneous tuberculosis.
Reference:
Spina, O., Fraimow, H., & Green, J. (2025). Cutaneous Tuberculosis Presenting as a Chronic Dermatologic Disorder. Case Reports in Dermatological Medicine, 2026(1), 3172006. https://doi.org/10.1155/crdm/3172006
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