A 60-year-old man who smokes presents to the physician's office smelling of alcohol. He complains of a black discoloration of his tongue and a gagging sensation on occasion. He admits to smoking 1 to 2 packs per day along with drinking at least 6 to 8 beers per day. The patient brushes his teeth infrequently and has not seen a dentist for a long time. On physical exam, his teeth are stained and his tongue is brown, coated with a hairlike appearance toward the posterior two-thirds (Figure 39-1). Diagnoses include black hairy tongue (BHT), poor oral hygiene, and tobacco and alcohol addiction.
Black hairy tongue showing elongated filiform papillae with brown discoloration in a man who is a heavy smoker and drinker. Note the tobacco-stained teeth. (Reproduced with permission from Brad Neville, DDS.)
BHT is a benign disorder characterized by the reactive hypertrophy of the filiform papillae of the tongue, which results in the clinical elongation of the papillae,1 providing the hairlike appearance of the dorsum of the tongue.2
Hyperkeratosis of the tongue, lingua villosa nigra.
The prevalence of BHT varies depending on the risk factors in the population being studied. However, several studies have consistently reported a higher prevalence in males compared with females.1 Increasing age also showed a positive correlation with a prevalence nearly 40% in patients over 60 years old.3
It can be as high as 57% in persons incarcerated or addicted to drugs.4
The prevalence in Minnesota schoolchildren was 0.06%.5
In Turkish dental patients, the highest prevalence was 54% in heavy smokers.3
ETIOLOGY AND PATHOPHYSIOLOGY
BHT (Figure 39-1) is a disorder characterized by the hypertrophy of filiform papillae and its defective desquamation that leads to an accumulation of keratinized layers.1,4,6
These papillae, which are normally about 1 mm in length, may become as long as 12 mm.
The elongated filiform papillae can then collect debris, bacteria, fungus, or other foreign materials which cause the characteristic black coloration.1
In an extensive literature review of reported cases of drug-induced BHT, 82% of the cases were caused by antibiotics (Figure 39-2).2
Medication-induced xerostomia (dry mouth), tobacco, and radiation therapy can lead to BHT.2
Drug-induced black hairy tongue with yellowish-brown elongated filiform papillae in a patient taking a broad-spectrum antibiotic. (Reproduced with permission from Richard P. Usatine, MD.)