Tumor necrosis factor (TNF) inhibitors, including adalimumab, are widely used to treat refractory psoriatic arthritis (PsA). Although isoniazid chemoprophylaxis is generally effective in preventing reactivation of latent tuberculosis infection (LTBI), prophylactic measures do not fully protect against development of active tuberculosis. We report a rare case of active tuberculosis despite chemoprophylaxis for LTBI in a patient receiving adalimumab for PsA. A 60-year-old Japanese woman who had received a diagnosis of psoriasis at age 35 years presented with arthralgia of the right hand, which she first noticed 2 months previously. Physical examination showed scattered erythematous papules and plaques with scales on her trunk, extremities, and scalp. Her right metacarpophalangeal and proximal interphalangeal joints were swollen and painful, and her right wrist and elbow were painful. PsA was diagnosed and adalimumab was initiated. Because an interferon-γ release assay (IGRA) showed a borderline result at screening, isoniazid was administered as chemoprophylaxis for LTBI. At 22 months after initiation of adalimumab, IGRA was positive and chest CT disclosed centrilobular nodules in both lungs and swelling of multiple lymph nodes. Culture of sputum at 24 months demonstrated Mycobacterium tuberculosis. Active tuberculosis was diagnosed, and treatment with a combination of isoniazid, rifampicin, ethambutol hydrochloride, and pyrazinamide was started. To ensure timely diagnosis and treatment of active tuberculosis, a tuberculosis expert should be consulted at an early stage, with regular screening and monitoring.
Keywords: active tuberculosis; adalimumab; chemoprophylaxis; latent tuberculosis infection; psoriatic arthritis.