Diagnosis: Hairy tongue

The patient was diagnosed with hairy tongue (lingua villosa), a benign condition that is often a result of poor oral hygiene. Previous theories inferring that this condition may be a harbinger of underlying systemic illness have been debunked. Environmental factors that contribute to its onset include smoking and hot beverages; recent evidence suggests that it may even be drug-induced.1 Hairy tongue affects approximately 0.5% of the population, with most patients being male.2

The dorsal surface of the tongue is covered with numerous filliform papillae—diffuse hairlike projections, which are
particularly prominent along the midline. In cases of hairy tongue, the normal papillae become elongated, twisted, and caked with keratinaceous debris. Although the condition is frequently referred to as “black hairy tongue,” the plaque may also appear brown, white, green, yellow, or even pink, depending on what exogenous substances (such as tobacco, bacteria, or food) mix with the keratin fragments. Patients (or their acquaintances) will often complain of a bad taste or malodorous breath. Supercolonization by commensal oral flora is a universal feature.


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A diagnosis of hairy tongue is always clinical, and no laboratory assays are required. Using a tongue blade, we scraped our patient’s lesion vigorously, resulting in the collection of a sticky brown film. Were a biopsy to be performed, microscopic examination would reveal heaped keratin admixed with bacteria, all atop filliform papillae.3

The differential diagnosis for hairy tongue includes Epstein-Barr virus-associated oral hairy leukoplakia (OHL) and oral candidiasis (thrush). Both conditions, seen in immunosuppressed patients, can be easily distinguished from hairy tongue. OHL has a shaggy, white appearance and is commonly seen on the lateral aspects of the tongue. Moreover, it cannot be removed with a tongue blade. In contrast, firm scraping will loosen thrush. Thrush exhibits a cottage-cheese color and texture over a beefy-red erythematous base.

Treatment for hairy tongue includes smoking cessation and keratolytics, such as 40% aqueous urea, that may be as difficult for the patient to apply as it is to obtain. Alternatively, retinoid gels may be tried; tretinoin 0.1% has shown documented success.4 Surgical therapy is reserved for the most recalcitrant cases.5 Mechanical debridement appears to be the most effective therapy. Twice-daily use of a firm toothbrush or tongue scraper can debulk much of the compacted keratin from the tongue. Coupled with smoking cessation, this usually results in >90% clearance of the offending plaque after three to four weeks.

Our patient was unable or unwilling to quit or reduce his tobacco habit. He used a toothbrush, as instructed above, for one month and experienced a moderate improvement in his tongue’s appearance.

Dr. Buka is a dermatology fellow in the Department of Dermatology, Children’s Hospital San Diego.

References

1. Heymann WR. Psychotropic agent-induced black hairy tongue. Cutis. 2000; 66:25-26.
2. Avcu N, Kanli A. The prevalence of tongue lesions in 5150 Turkish dental outpatients. Oral Dis. 2003;9:188-195.
3. Manabe M, Lim HW, Winzer M, Loomis CA. Architectural organization of filiform papillae in normal and black hairy tongue epithelium: dissection of differentiation pathways in a complex human epithelium according to their patterns of keratin expression. Arch Dermatol. 1999;135:177-181.
4. Langtry JA, Carr MM, Steele MC, Ive FA. Topical tretinoin: a new treatment for black hairy tongue (lingua villosa nigra). Clin Exp Dermatol. 1992;17:163-164.
5. Seoane J, Vazquez J, Pomareda M, Argila F. Surgical treatment of hairy black tongue [In Spanish]. Acta Otorrinolaringol Esp. 1997;48:173-174.