What is hairy tongue?
Hairy tongue is an unusual, harmless condition characterised by a 'hairy' enlargement and discolouration of the filiform papillae. The filiform papillae are tiny conical bumps found on the surface of the front two-thirds of the tongue that do not carry taste buds.
It is also known as black hairy tongue and lingua villosa nigra.
Who gets hairy tongue?
Hairy tongue most often occurs in adults over 40 years of age and is rare in infants .
A range of medications have been linked to hairy tongue including penicillin, erythromycin, tetracycline, doxycycline, lansoprazole, olanzapine, bismuth , erlotinib , linezolid .
Other factors that may cause, and/or aggravate hairy tongue include:
- Poor oral hygiene
- Smoking or chewing tobacco
- Drinking alcohol
- Chlorhexidine or peroxidase-containing mouthwash
- Coloured beverages, including coffee
- Hyposalivation (dry mouth)
- Radiation therapy .
What are the clinical features of hairy tongue?
The filiform papillae can grow up to 18 mm in length—a ‘hairy’ appearance . The tongue becomes discoloured, usually brown or black, although brown, yellow and green have also been described . The back surface of the tongue is usually affected, and the tip and sides of the tongue are often spared .
Hairy tongue is usually asymptomatic and the main problem is its unsightly appearance. Occasionally patients may complain of a burning or tickling sensation on the tongue, nausea, or halitosis (bad breath).
Black hairy tongue
What causes hairy tongue?
Hairy tongue is due to defective shedding of surface cells. Abnormal filiform papillae prevent normal cleaning and debridement of the tongue, hence debris accumulates. Bacteria and yeasts then overgrow and make porphyrins (deeply coloured organic compounds), which may contribute to the discolouration .
How is hairy tongue diagnosed?
Hairy tongue is a clinical diagnosis .
It is important to take a detailed history to establish possible contributing factors. Investigations may include:
What is the treatment of hairy tongue?
Hairy tongue is usually self-limiting. If desired, treatment options include:
- Discontinuing responsible drugs
- Avoiding smoking and excessive alcohol intake
- Encouraging good oral hygiene
- Gentle tongue debridement, with a tongue scraper or soft toothbrush and solution containing 3% hydrogen peroxide or baking soda 
- Antiseptic mouthwash
- Topical antifungal agent for oral Candida albicans if present
- Topical retinoid
If other treatment fails, trimming papillae by carbon dioxide laser burning and electrodessication have been described .