Topical tretinoin: a new treatment for black hairy tongue (lingua villosa nigra).

Black hairy tongue is the name given to the appearance of an abnormal coating of the tongue and occurs only in adults. It is the result of hyperkeratosis of the filiform lingual papillae which, on gross examination appear hair-like with a variable tinctorial aspect from yellow-brown to black. The pathogenesis is unknown and often no definite cause can be identified. A number of aetiologic factors have been implicated including the administration of topical or systemic antibiotics, poor oral hygiene, smoking, alcohol and the use of mouthwashes. Often there are no symptoms other than the aesthetic or anxiety over its aetiology. Some patients complain of gagging, nausea, alteration of taste or halitosis. The condition may be very persistent and recognized treatments include brushing with a soft tooth brush which is enhanced by the prior application of a 40% solution of urea, scraping, topical triamcinolone acetonide, gentian violet, thymol, salicylic acid, vitamin B complex, and surgical excision of the papillae.