Black Hairy Tongue

Black hairy tongue (lingua villosa nigra) is a benign condition caused by hypertrophy and elongation of the filiform papillae of the dorsal tongue, which fail to desquamate normally and trap bacteria, yeasts, food debris and pigment, giving a brown, black, yellow or green hairy appearance. Prevalence is 0.5 to 11 percent, higher in men, older adults, smokers and those who use tobacco, coffee or tea heavily.

Normal filiform papillae are 1 mm long; in this condition they reach 10 to 18 mm. Discolouration comes from chromogenic bacteria (Prevotella, Staphylococcus aureus), porphyrin production, tobacco, coffee, chlorhexidine, and foods.

Precipitating factors are broad spectrum antibiotics (tetracyclines, penicillins, erythromycin, linezolid), oxidising mouthwashes (hydrogen peroxide, sodium perborate), poor oral hygiene, radiotherapy to the head and neck, dehydration and xerostomia, intravenous drug use, HIV, diabetes, bismuth preparations, and olanzapine. The condition is harmless and fully reversible.

• Brown, black, yellow, green or white hair like coating of the posterior two thirds of the dorsal tongue, sparing the tip and sides.
• Often asymptomatic; cosmetic concern.
• Halitosis, altered taste (dysgeusia), metallic taste, gagging or tickling of the palate, nausea, burning if candidal infection coexists.
• Papillae up to 1 cm long.
• Red flags: persistent ulceration, induration, lymphadenopathy, unexplained weight loss, or a non-scrapable pigmented lesion (consider melanoma or other pigmented lesion).

• Clinical diagnosis from the characteristic appearance; pigmentation is superficial and does not scrape off completely.
• Medication history (antibiotics, bismuth, chlorhexidine, olanzapine), habits (tobacco, tea, coffee), and oral hygiene review.
• Swab or smear for Candida species if the tongue is sore, red or sore edged.
• Blood tests if recurrent: glucose or HbA1c, full blood count, HIV test in those with risk factors.
• Biopsy is only for atypical lesions; histology shows elongated, hyperkeratotic filiform papillae with bacteria and debris.
• Exclude oral hairy leukoplakia (lateral tongue ridges, non-scrapable), pigmented lesions (melanoma, melanotic macule), oral candidiasis, leukoplakia, geographic tongue, and pseudomembranes.

• Remove contributing factors: stop smoking, reduce tea and coffee, stop or replace implicated drugs where possible, and discontinue chlorhexidine or oxidising mouthwashes.
• Oral hygiene is the key treatment: brush the dorsum of the tongue with a soft toothbrush or tongue scraper twice daily, starting from the back and moving forward; rinse with water after meals.
• Sodium bicarbonate rinse (5 percent, 1 teaspoon in a cup of warm water) 3 times daily for 2 weeks may loosen debris.
• Hydration: 2 litres of water daily, chewing sugar free gum to stimulate saliva.
• Candida co-infection: nystatin oral suspension 100 000 units/mL, 5 mL four times daily for 7 to 14 days; or fluconazole 50 mg orally once daily for 7 to 14 days.
• Topical keratolytic or retinoid: tretinoin 0.025 percent applied to the tongue dorsum, or urea 40 percent paste, in refractory cases, under specialist care (rarely needed).
• Papillae of excessive length may be trimmed (electrocautery, laser, or surgical clipping) in recalcitrant cases.
• Follow up: usually resolves within 2 to 8 weeks of modifying causes; review at 4 weeks.
• Counselling: the condition is harmless; recurrence is common if the triggers are repeated.