Patient develops black tongue discolouration after taking antibiotic treatment: Case Report

Japan: A recent case study published in the Journal of the American Medical Association (JAMA) describes the case of a patient with subscapularis pyomyositis who developed black tongue discolouration following treatment with antibiotics for a methicillin-susceptible Staphylococcus aureus infection. 

The case reported by Yasuhiro Kano, Tokyo Metropolitan Tama Medical Center, Tokyo, Japan, concerns an 80-year-old male patient with subscapularis pyomyositis undergoing intravenous (IV) antibiotic treatment for a methicillin-susceptible Staphylococcus aureus infection. Seven days after initiating antibiotics, he developed asymptomatic black discolouration of the dorsal surface of the tongue. 

Black hairy tongue, presenting as black discolouration on the dorsal surface of the tongue with hypertrophic filiform papillae, may be associated with antibiotics, antipsychotic drugs that cause xerostomia, and some chemotherapeutic agents. This condition is more common among males and geriatric patients and is primarily diagnosed by visual inspection.

The man was presented to the emergency department (ED) with a 5-day history of fever and right shoulder pain. His body temperature was 100.2 °F, blood pressure 90/49 mm Hg, and heart rate 74/min. He had decreased range of motion in his right shoulder and tenderness to palpation. Laboratory testing revealed a WBC (white blood cell) count of 9.6 ×  109/L (reference, 4.0-9.0 × 109/L); creatine kinase level, 1036 U/L (reference, 60-270 U/L); and C-reactive protein level, 35.6 mg/dL (reference, <0.3 mg/dL). 

MRI (magnetic resonance imaging) revealed an effusion and synovial thickening with enhancement in the right shoulder joint and inflammation in the right subscapularis muscle. Gram stain of the synovial fluid showed gram-positive cocci in clusters. IV cefazolin therapy was initiated, and he underwent right shoulder joint arthroscopic irrigation, surgical drainage, and synovectomy for subscapularis pyomyositis. Intravenous cefazolin was continued, and blood and synovial fluid cultures grew methicillin-susceptible S. aureus. 

One week after hospital admission, the patient developed asymptomatic black discolouration of the dorsal surface of his tongue. He reported no prior lingual discolouration and did not use chewing tobacco or illicit drugs, smoke cigarettes, or drink alcohol.

Black hairy tongue treatment comprises reassuring the patient, gentle debridement with a soft toothbrush or tongue scraper, removing causative factors, and improving oral hygiene. Topical application of diluted hydrogen peroxide or baking soda slurry promotes desquamation of the hyperkeratotic papillae.

Reference:

Kano Y. Black Tongue Discoloration. JAMA. Published online May 12, 2023. doi:10.1001/jama.2023.5894