Hairy leukoplakia  is a white patch on the side of the tongue with a corrugated or hairy appearance. It is caused by Epstein-Barr virus (EBV) and occurs usually in persons who are immunocompromised, especially those with human immunodeficiency virus infection/acquired immunodeficiency syndrome (HIV/AIDS). The white lesion, which cannot be scraped off, is benign and does not require any treatment, although its appearance may have diagnostic and prognostic implications for the underlying condition. Depending upon what definition of leukoplakia is used, hairy leukoplakia is sometimes considered a subtype of leukoplakia, or a distinct diagnosis. Signs and symptoms
There are no symptoms associated with the lesion itself, although many and varied symptoms and signs may be associated with the underlying cause of immunosuppression. The lesion is a white patch, which almost exclusively occurs on the lateral surfaces of the tongue, although rarely it may occur on the buccal mucosa, soft palate, pharynx or esophagus. The lesion may grow to involve the dorsal surface of the tongue. The texture is vertically corrugated ("hairy") or thickly furrowed and shaggy in appearance. Causes
The white appearance is created by hyperkeratosis (overproduction of keratin) and epithelial hyperplasia. The causative agent implicated is Epstein-Barr virus, the same virus that causes infectious mononucleosis (glandular fever). After the primary EBV infection has been overcome, the virus will persist for the rest of the hosts life and "hides" from the immune system by latent infection of B lymphocytes.
For instance, OHL with HIV/AIDS is a predictor of bad prognosis, (i.e. severe immunosuppression and advanced disease). Epidemiology
Hairy leukoplakia is one of the most common oral manifestations of HIV/AIDS, along with oral candidiasis. It is the most common HIV/AIDS related condition caused by EBV, although EBV associated lymphomas may also occur. OHL mainly occurs in adult males, less commonly in adult females and rarely in children. The incidence rises as the CD4 count falls, and the appearance of OHL may signify progression of HIV to AIDS. A study from 2001 reported a significant decrease in the incidence of some oral manifestations of AIDS (including OHL and necrotizing ulcerative periodontitis), which was attributed to the use of HAART, whilst the incidence of other HIV-associated oral lesions did not alter significantly. History
Oral hairy leukoplakia was discovered by Deborah Greenspan and John S. Greenspan, and in 1985 they identified a connection between it and Epstein-Barr virus (EBV). Oral hairy leukoplakia was first described by Greenspan et al. in 1984, a few years after the start of the AIDS epidemic. A link with OHL was not initially reported as scientific understanding of HIV/AIDS was just beginning to develop at that time. It was subsequently thought to occur only in HIV-infected, homosexual males, however, this is now known to not always be the case. Research directions
It has been suggested that OHL be renamed according to its causative factor as “EBV leucoplakia”. References


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