A recent report from researchers at Fukuoka University in Japan described a rare case of black hairy tongue in a woman receiving antibiotic therapy. The case was documented in a health report published within BMJ Case Reports. The description highlights how a seemingly unusual change in tongue appearance can arise during medical treatment and how clinicians interpret such changes.
The patient involved was a 60 year old woman treated for rectal cancer. During the course of her therapy she developed a noticeably dark, hairy-appearing tongue. Black hairy tongue is a benign and reversible condition that produces a deep discoloration of the tongue surface. The underlying mechanism involves the accumulation of dead cells on the top surface of the tongue, particularly in the filiform papillae that give the tongue its rough texture and contain taste buds. When these papillae elongate or shed at altered rates, they can trap debris and pigment, leading to the characteristic black or dark brown hue.
At the time of observation, the patient had been on antibiotic treatment for about fourteen months. The antibiotic was administered in a regimen of 100 milligrams every other day with the aim of preventing skin lesions that might be induced by the anti cancer drug panitumumab. This medication plan reflects a common approach in cancer care, where antibiotics are used to minimize infection risks and manage side effects associated with targeted therapies.
During the same evaluation, clinicians noted gray patches on the patient’s facial skin. The gray pigment is consistent with known reactions to certain antibiotics, including minocycline, where oxidation of the drug can lead to pigment darkening of the skin. This observation helped support the interpretation that the tongue discoloration and skin changes were related phenomena related to antibiotic exposure rather than a primary mucosal disease or cancer progression.
After a follow up period of six weeks, the visible improvements were notable. Both the facial pigmentation and the black tongue changes showed marked reduction, aligning with the understanding that these are reversible side effects when the triggering antibiotic exposure is managed or discontinued. The clinicians concluded that the most likely cause of the patient’s symptoms was a drug reaction to minocycline or a similar antibiotic used during the cancer treatment pathway.
Black hairy tongue can be accompanied by additional sensory changes. Patients may report an altered or metallic taste, foul breath, or a mild nausea or tickling sensation in the mouth. The precise cause of black hairy tongue can be multifactorial and does not always point to a single diagnosis. In many cases, contributing factors include antibiotic use, suboptimal oral hygiene, frequent use of certain mouthwashes, and lifestyle habits such as smoking or consuming coffee, tea, and alcohol. Maintaining good oral hygiene, regular dental checkups, and reviewing medication plans with healthcare providers can help reduce the risk or severity of these changes. In situations where a drug is suspected to cause pigment changes or mucosal reactions, clinicians may consider adjusting the regimen or exploring alternative therapies to alleviate symptoms while continuing essential cancer treatment. This balanced approach helps preserve patient comfort and overall treatment effectiveness while avoiding unnecessary interruptions in care.