Black Hairy Tongue Should Not Lead to Linezolid Discontinuation in Rifampicin-resistant Tuberculosis

To the Editors: We read with great interest the recent clinical case study by Jain et al., of a child with black hairy tongue (BHT) who was receiving second-line antituberculosis therapy for rifampicin-resistant tuberculosis, including linezolid.1 However, we believe that a reader who only skims the article might conclude that the appropriate course of action in such cases is to discontinue linezolid. However, we would like to clarify that BHT alone does not justify discontinuing linezolid in patients with rifampicin-resistant or multidrug-resistant tuberculosis. As the authors themselves point out, BHT is a recognized benign and reversible adverse effect of linezolid, caused by hypertrophy of the filiform papillae with the subsequent accumulation of bacteria and debris, producing the characteristic dark discoloration of the tongue.2 This side effect is mild and cosmetic in nature, with no serious clinical implications.2,3 In most cases, it resolves spontaneously or with simple local measures while treatment with linezolid continues.2,3 The recommended management consists of gently brushing the tongue 2 or 3 times a day with a toothbrush or tongue scraper, maintaining rigorous oral hygiene and avoiding predisposing factors wherever possible.3 Cases described in the literature show that linezolid-induced BHT resolves with these conservative measures, even when the antibiotic is continued. In 1 documented case, the lesion reappeared after the drug was reintroduced, but resolved again without the need for permanent discontinuation.3 For patients with rifampicin-resistant multiorgan tuberculosis, linezolid is an essential, potentially life-saving drug that forms part of the short-course bedaquiline, pretomanid, and linezolid or bedaquiline, pretomanid, linezolid and moxifloxacin regimens recommended by the American Thoracic Society/Centers for Disease Control and Prevention/European Respiratory Society/Infectious Diseases Society of America guidelines.4,5 Data from pediatric cohorts confirm its efficacy and manageable safety profile under adequate monitoring.6,7 Premature discontinuation of linezolid due to a benign mucosal reaction could compromise therapeutic success in a potentially fatal disease. Therefore, we recommend recognizing this self-limiting reaction and, wherever possible, continuing linezolid alongside local hygiene measures to avoid interrupting critical therapy.