Hairy leukoplakia is a patch of white observed laterally on the tongue with a typical ridged appearance. It is associated with conditions leading to immunodeficiency and primarily AIDS syndrome and is mainly caused by the Epstein-Barr virus.
Leukoplakia involves white, flat, smooth, hairy-like patches forming at the sides of the tongue  and not necessarily in a symmetric fashion: both or only one side may be involved. These patches often produce no symptoms  and may go away and reappear automatically, also changing their appearance while they are present. They may either appear continuously or separately along the lateral sides of the tongue and can also expand to the ventral or dorsal side. Typically, scraping the lesions will produce no results, as it will only separate the superficial layers from the underlying ones; this feature differentiates hairy leukoplakia lesions from a candida infection. Regions where the paths have become thicker or stiffer may appear and, seldom, they can be observed on the pharynx or esophagus. Should symptoms be produced, these involve moderate pain  and unnatural sensation in the tongue and an impaired sense of taste. Other than the lesions themselves, the tongue exhibits no signs of inflammation and patients are many times concerned about aesthetic reasons  .
In cases where the patches appeared inflamed, red and raised, suspicion for an underlying malignancy should be raised, although this is a rare phenomenon.
Hairy leukoplakia can be diagnosed either by a histologic examination of a biopsy specimen retrieved from the tongue, or by a cytologic examination of superficial cells . As far as histopathological features are concerned, the most typical findings in patients with hairy leukoplakia include the following 5 characteristics :
A definitive diagnosis of hairy leukoplakia cannot be established with the aforementioned observations alone, as none is pathognomonic to the condition. Matching histologic and cytologic findings, alongside the confirmation of an EBV infection are necessary for such a diagnosis. However, these procedures are likely not to be performed, as they are reserved only for patients with a suspected underlying malignancy.
Since hairy leukoplakia arises as a result of a persistent EBV infection on the grounds of immunosuppression and none of the two conditions can be eradicated, it is not expected to respond long-term well to therapeutic measures. Antiviral agents are administered, which resolve the condition within 1 or 2 weeks , including acyclovir (800 mg, 5 times per day ), valacyclovir (3 times per day, 1g) and famcyclovir (500 mg, 3 times a day). These agents hinder the reproduction of EBV, reducing the infection to a state of latency.
Podophyllin resin solution can also be applied locally, even though it may cause pain and taste impairment and patients relapse after several weeks . Patients with smaller lesions can be candidates for ablation therapy and cryotherapy has also produced positive results, remaining, however, limited in use .
The administration of HAART (highly active antiretroviral therapy) against the HIV virus has succeeded in decreasing the number of patients who develop hairy leukoplakia.
The prognosis of patients exhibiting hairy leukoplakia is directly related to their CD4 T count. Even though almost all patients exhibit a considerable degree of immunodeficiency when the condition is diagnosed, patients' CD4 T count usually ranges from 235 to 468 per cubic milliliter. In individuals with a count greater or equal to 300, the average survival time is expected to be 25 months. On the contrary, patients with normal counts are expected to have a median survival of 52 months. In general, hairy leukoplakia is first detected after HIV antibodies have started to be produced and the average survival time of all patients is estimated to be around 20 months upon diagnosis.
Hairy leukoplakia is believed to be a result of the Epstein-Barr virus, one of the viruses belonging to the group of Herpesviridae (or herpes viruses) . It is transferred from one person to another and it is an extremely common virus which affects a staggering percentage of worldwide population. During the period of adolescence or early adulthood, the EB virus causes mononucleosis.
EBV typically remains dormant in a person's organism after the very first infection. If the immune system is weakened, such as in HIV-positive individuals who are moderately or severely immunodeficient, the Epstein-Barr virus is reactivated, causing the oral infection known as hairy leukoplakia .
Hairy leukoplakia is one of the most frequent complications of a HIV infection, with the point prevalence amounting to 25% amongst HIV-positive individuals . As far as the risk factors for developing hairy leukoplakia on the grounds of HIV are concerned, it is believed that male sex and a smoking habit increase the possibility of exhibiting it .
A definitive connection between the CD4 T count and the onset of hairy leukoplakia has yet to be established; it is generally known that it can also arise in patients with a CD4 T count greater than 500 cells/cubic millimeter. New radical antiretroviral therapies alongside medications against the herpesviridae have contributed to the decline of hairy leukoplakia prevalence amongst HIV patients.
All herpesviruses infect the host for the latter's entire life and EBV is no exception. The pharyngeal basal epithelial cells are the first to be infected by the virus; as it reproduces within the cells, it also infiltrates type B white cells, where it is harbored. Cytotoxic T lymphocytes are unable to exterminate the virus, but do, however, contribute greatly to the preservation of the latency state of the virus. This is why defects of the immune system leading to a decrease in the cytotoxic lymphocytes' number cause a reactivation of EBV.
The Epstein-Barr virus can be found throughout the world and is one of the most common viral agents, infecting approximately 90% of the population. Hairy leukoplakia is itself caused by a reactivation of EBV in immunosuppressed patients, following a complex pathogenetic path. It is believed that this reactivation is facilitated when a person is infected anew by EBV. Other researchers have suggested that the viral genome evolves to escape eradication and that specific genes contribute to its latency period. Findings that reveal a diminished number of Langerhans cells in biopsy specimens from hairy leukoplakia patients further illustrate how the virus escapes eradication mechanisms, given the antigen-presentation ability of these cells  . At any case, both systemic and local host immunosuppression are vital factors, contributing to the viral regeneration pattern .
Maintaining an immune system that is as potent as possible is the key to avoiding hairy leukoplakia. Patients need to follow their drug regimen responsibly, eat healthy, quit smoking, exercise regularly and use protection when engaging in sexual intercourse. A doctor or healthcare provider is the person responsible for deciding on a therapeutic plan and for making any adaptation needed.
Hairy leukoplakia is a medical condition which causes white lesions with hairy-like features, appearing at the sides of the tongue. It is caused by the Epstein-Barr virus (EBV). After the initial EBV infection, the virus displays a latency feature, namely it remains in the organism without causing any type of symptomatology, only to be reactivated under certain circumstances: a potential compromise of the immune system. This is why hairy leukoplakia is mainly associated with the HIV infection and more specifically, the AIDS syndrome or AIDS-related complex (ARC).
Other circumstances, under which a reactivation of EBV and subsequently hairy leukoplakia could occur, include organ transplants and the administration of chemotherapy  . A patient is rendered immunodeficient and the ground is fertile for the EB virus to be regenerated.
Hairy leukoplakia is a non-malignant condition and it is sometimes an indication of unsuccessful HIV treatment. It can also be the first sign of immunocompromise due to an undiagnosed HIV infection or a sign of a secondary infection. At any case, it is a marker whose appearance shows that the immune system is impaired.
Hairy leukoplakia is a condition which causes white patches to appear at the sides of the tongue, which exhibit a characteristic hairy-like appearance. They arise when a person's immune system is weak and are mainly associated with an HIV infection or other causes of immunodeficiency.
The Epstein-Barr (EBV) virus is believed to be responsible for the onset of hairy leukoplakia. EBV infects a person and then remains in their organism indefinitely. The virus can be reactivated when the carrier has a weak immune system and hairy leukoplakia emerges. Conditions that cause immunosuppression involve HIV (primarily) and people with autoimmune diseases (eg. ulcerative colitis) or those who have received transplants.
Men with a weakened immune system and particularly those who smoke run a higher risk of developing hairy leukoplakia than women.
Hairy leukoplakia could be the first indication that a person has been infected with the HIV virus and that their immune system is declining. Typical manifestations include white patches that appear either on both sides of the tongue or on one only. The patches are usually not painful and appear as though covered by short hair. In some locations, those lesions may appear thicker or harder and they can rarely be observed on the pharynx too. If the lesions start to be painful, a doctor should be promptly consulted, as an underlying cancer may be present.
Hairy leukoplakia can be diagnosed by a biopsy, a cell sample brushed off the tongue and further examinations. Not every patient needs to undergo all these procedures and most are diagnosed with clinical criteria. If a person is a known HIV-positive patient or has any other type of diagnosed immunodeficiency, the doctor will proceed to treating hairy leukoplakia. If an otherwise healthy individual exhibits the white lesions, they need to be examined in order to determine what lead to such a disease.
Hairy leukoplakia is, in the majority of the cases, a direct result of an underlying immunodeficiency. Therefore, treating it alone is like treating the symptom and not the disease. In order to potentially eliminate the lesions and provide a patient with better standards of living, the cause of immunodeficiency must be treated. In cases of HIV or AIDS, strong antiviral agents are administered, which hinder the reproduction of the HIV virus and help to exterminate hairy lesions. Other antiviral drugs like acyclovir, ganciclovir or valacyclovir can be administered to treat the symptom, if the patients are not treated for HIV and the lesions cause problems with taste or pain. Antifungal drugs also help treat co-infection with Candida.