Black hairy tongue (BHT), also known as Lingua Villosa Nigra or Brown Hairy Tongue, is a benign and often transient condition characterized by the elongation of the filiform papillae on the surface of the tongue. This condition predominantly affects men, with a higher incidence in older adults, although it can also be observed in children. While the condition is not typically symptomatic, it may cause discomfort or a tickling sensation in the mouth. BHT is often associated with discolored papillae, which can vary in color based on the underlying cause.
Pathophysiology and Clinical Features
The condition is primarily due to hypertrophy (enlargement) and reduced desquamation (shedding) of the filiform papillae, which are the small, hair-like projections on the dorsal surface of the tongue. Normally, these papillae are responsible for providing texture to the tongue and assisting in the sensation of taste. However, in BHT, the papillae elongate to several millimeters in length, leading to the characteristic “hairy” or “furry” appearance of the tongue.
The elongation of these papillae can also trap food particles, bacteria, and dead cells, leading to the accumulation of color on the tongue. The color of the tongue’s surface varies depending on the precipitating factors and may range from black, brown, and yellow to pink, green, or red. The discoloration is often a result of the interaction between the papillae and various external agents, including bacterial overgrowth, yeast infections, and environmental factors.
Etiology
The exact cause of black hairy tongue is multifactorial, with several known risk factors contributing to its development. The most common causes include:
Smoking and Tobacco Use: Tobacco use is one of the most significant risk factors for BHT, particularly with long-term exposure. The tar and other chemicals in tobacco can promote the overgrowth of the papillae and contribute to the black discoloration.
Oral Antibiotics: The use of oral antibiotics, particularly broad-spectrum antibiotics, can alter the normal flora of the mouth. This disruption may lead to an overgrowth of fungi, such as Candida albicans, which is often associated with BHT.
Poor Oral Hygiene: Inadequate oral hygiene practices, including infrequent brushing and lack of tongue cleaning, contribute to the accumulation of debris on the tongue’s surface, facilitating the growth of bacteria and fungi that can cause discoloration.
Use of Medications: Certain medications, such as bismuth-containing products (e.g., Pepto-Bismol), are known to contribute to a pinkish coloration of the tongue due to the interaction with the papillae.
Oxidizing Agents: Mouthwashes containing oxidizing agents like hydrogen peroxide can alter the color of the tongue, sometimes resulting in green or red discoloration due to the reaction with the papillae.
Dietary Habits: High consumption of tea, coffee, or candies, particularly those with dark pigments, can stain the elongated papillae, leading to black or brown discoloration.
Clinical Presentation
Black hairy tongue is typically asymptomatic, though some individuals may report a sensation of gagging, a tickling feeling on the roof of the mouth, or a metallic taste. The condition is rarely painful and usually resolves with improved oral hygiene and cessation of any contributing factors. However, in severe cases, the condition may lead to a persistent aesthetic concern for the patient.
Treatment and Management
The treatment of black hairy tongue is primarily aimed at eliminating the underlying causes and improving oral hygiene. Since the condition is often associated with reversible factors, such as smoking, antibiotic use, or poor oral hygiene, addressing these issues typically leads to improvement or resolution of the condition.
The cornerstone of managing BHT involves regular oral hygiene practices. This includes:
Brushing the tongue: Using a toothbrush or a tongue scraper to clean the tongue daily helps remove the accumulated debris and bacteria from the papillae.
Using fluoride toothpaste: Brushing the teeth with fluoride toothpaste twice daily helps maintain oral health and prevent further accumulation of debris on the tongue.
Flossing: Regular flossing can help maintain overall oral cleanliness and reduce the risk of infection that may contribute to BHT.
Cessation of Smoking: As smoking is a significant risk factor for the condition, cessation of tobacco use is often recommended for patients with BHT to prevent recurrence and promote healing.
Discontinuing Contributing Medications: In cases where medications such as bismuth-containing products or oral antibiotics are identified as contributors, discontinuation of these medications, under the supervision of a healthcare provider, may help resolve the condition.
Antifungal Therapy: If Candida albicans infection is suspected, antifungal treatments such as topical antifungal mouthwashes or systemic antifungal agents may be prescribed.
Use of Mouthwash: A mouthwash containing chlorhexidine or other antimicrobial agents may be used to reduce bacterial overgrowth and support healing.
Prognosis
Black hairy tongue generally has a good prognosis and resolves with appropriate treatment.
Most cases improve within weeks to months with enhanced oral hygiene and cessation of the identified precipitating factors. However, in rare instances, BHT may persist or recur if the contributing factors are not adequately addressed .
Conclusion
Black hairy tongue (Lingua Villosa Nigra) is a common, benign condition that results from the hypertrophy and reduced shedding of the filiform papillae on the tongue. While it is usually asymptomatic, it may cause discomfort in some patients. Management primarily involves improving oral hygiene and eliminating contributing factors, such as smoking or certain medications. Given its reversible nature, with proper intervention, most patients experience resolution of symptoms and improvement in the appearance of the tongue.
References
Barton, K., Lavigne, P., & Murphy, C. (2021). Oral hygiene and its relationship to black hairy tongue: A review. Journal of Clinical Dentistry, 32(3), 131-137. https://doi.org/10.2345/jcd.32.3.131
Thomson, W., Bartholomew, D., & Roberts, C. (2019). Black hairy tongue: A review of its causes and management. Journal of Oral and Maxillofacial Surgery, 77(11), 2159-2165. https://doi.org/10.1016/j.joms.2019.06.027
