Wiley Acta Medica Okayama 2050-0904 14 8 2026 Black Hairy Tongue in a 54�]Day�]Old Infant: A Case Report e73170 EN Masanori Masui Department of Oral and Maxillofacial Surgery, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Yumi Sakamoto Department of Oral and Maxillofacial Surgery, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Yuki Kunisada Department of Oral and Maxillofacial Surgery, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Soichiro Ibaragi Department of Oral and Maxillofacial Surgery, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Black hairy tongue is a benign condition caused by elongation and defective desquamation of the filiform papillae, and it is uncommon in neonates and infants. We report a case in a 54-day-old girl who presented with a black lesion on the tongue dorsum. The lesion had first been noted at the 1-month medical checkup and persisted despite observation. At presentation, a localized blackish-brown lesion with accentuated filiform papillae was observed on the tongue dorsum and could not be wiped off with gauze. Oral candidiasis was considered in the differential diagnosis, but microbiological examination detected no Candida species. A clinical diagnosis of black hairy tongue was made, and the parents were instructed to gently clean the tongue dorsum with gauze and a sponge brush. The lesion resolved within 2 weeks without recurrence. Recognition of this benign entity may help avoid unnecessary treatment in infants. No potential conflict of interest relevant to this article was reported.