Symptoms
In black hairy tongue, a colored, hairy coating appears on the middle and back portions of the tongue. The discoloration can be black, gray, green, brown, and yellow. Itching, burning of the tongue, bad breath, changes in taste, metallic taste, nausea and lack of appetite are other possible symptoms. When swallowed, the “hairs” may cause a tickling sensation or nausea. Hairy tongue may disappear on its own or persist for a long time.
Causes
It is a benign, hyperkeratotic extension of the filiform papillae (thread papillae) on the tongue, which grow from about 1 mm to a maximum of 1.8 cm (!) and form the furry coating. The papillae are stained on the one hand by pigment-forming bacteria and partly by secondary infections with , on the other hand also by the ingested food and stimulants or medications. A strong burning of the tongue often occurs with a superinfection with . Although many possible risk factors are known (see below), the exact cause has not yet been elucidated. A change in the local environment in the oral cavity (flora, pH, tongue movements) is suspected. This is triggered by antibiotics, for example. Also of importance seems to be poor oral hygiene and reduced scraping of the tongue on the teeth, palate and food, e.g. when taking liquid food.
Complications
It is a benign change of the tongue surface and primarily an aesthetic problem. Although it is often described as harmless, it can cause distress to patients.
Risk factors and triggers
Potential factors include:
- Heavy consumption of stimulants such as cigarettes, tea, coffee, and alcohol.
- Bacteria, fungi
- Medications: Antibiotics (eg, linezolid, tetracyclines, doxycycline, erythromycin), antifungals, glucocorticoids, antacids, psychotropic drugs, phenothiazines, olanzapine, drugs that cause dry mouth.
- Radiation treatment
- Drug addiction
- Irritating substances, e.g., strong mouthwashes, mouth rinses (e.g., hydrogen peroxide), lozenges.
- Food, e.g. sunflower seeds.
- Deficiency of vitamin B, niacin
- Immunosuppression, HIV
- Dehydration, dry mouth
- Trigeminal neuralgia
- Male sex
- Age
Diagnosis
The diagnosis should be made in medical treatment. The most important criterion is the extension of the papillae over 3 mm. This is because the tongue may also be temporarily colored without papillae extension, for example, when bismuth salts, blueberries and other fruits, red wines, or mouthwashes are used. Other diseases such as hairy leukoplakia, acanthosis nigricans, candidamycosis or pigmentation of the fungiform papillae may cause a similar picture. It is important to ask the patient in detail about the risk factors so that they can be eliminated.
Nonpharmacologic treatment
The first-line measure is regular cleaning of the plaque with a soft toothbrush or tongue cleaner and good oral hygiene with a mild toothpaste. This removes impurities and the papillae and prevents reoccurrence. However, care must be taken to discontinue strong mouthwashes, as they may promote or trigger discomfort. The risk factors should be eliminated if possible. For example, discoloration disappears after discontinuing or reducing the dose of triggering medications. If dry mouth is present, attention should be paid to adequate hydration. Surgical removal under local anesthesia is not the first-line treatment, but may be indicated if the course is severe or prolonged.
Drug treatment
Medications are 2nd-line agents. Because it is a cornification disorder, keratolytics such as trichloroacetic acid, salicylic acid, or urea – in appropriate dilutions! – can be applied locally. They should be prescribed by a physician. Local vitamin C, tretinoin and the bleaching and disinfecting hydrogen peroxide are also mentioned as options in the literature. However, hydrogen peroxide in mouthwashes can also cause black hair tongue and must be diluted accordingly.External or internal antimycotics are only used if a secondary fungal colonization is also present. Mouth rinses should be used for treatment only with caution (risk factor, see above). Systemic isotretinoin may be considered for treatment of severe cases. The numerous precautions must be observed. Treatment can cause myriad side effects.
