Hairy leukoplakia
Encyclopedia
Hairy leukoplakia is a white patch on the side of the tongue with a corrugated or hairy appearance.
is seen in severe defects of immunity
, particularly in HIV
infection. The cause of this condition is an opportunistic infection
by the Epstein-Barr virus
(EBV). After the primary EBV infection has been overcome, the virus stays latent in the B cell
s and also causes lytic infection
in the oropharynx
, controlled by the immune system. Uncontrolled lytic infection in the oropharynx is manifested as oral hairy leukoplakia in immunosuppressed hosts. Oral hairy leukoplakia is not associated with any malignant
potential.
In 1992, the University of Connecticut School of Dental Medicine reported on two cases of oral hairy leukoplakia occurring in patients without any risk factors for HIV infection, or any other evidence of immune deficiency. It has been observed in patients on steroid
therapy.
Causes
Hairy leukoplakiaLeukoplakia
Leukoplakia is a clinical term used to describe patches of keratosis. It is visible as adherent white patches on the mucous membranes of the oral cavity, including the tongue, but also other areas of the gastro-intestinal tract, urinary tract and the genitals. The clinical appearance is highly...
is seen in severe defects of immunity
Immunity (medical)
Immunity is a biological term that describes a state of having sufficient biological defenses to avoid infection, disease, or other unwanted biological invasion. Immunity involves both specific and non-specific components. The non-specific components act either as barriers or as eliminators of wide...
, particularly in HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...
infection. The cause of this condition is an opportunistic infection
Opportunistic infection
An opportunistic infection is an infection caused by pathogens, particularly opportunistic pathogens—those that take advantage of certain situations—such as bacterial, viral, fungal or protozoan infections that usually do not cause disease in a healthy host, one with a healthy immune system...
by the Epstein-Barr virus
Epstein-Barr virus
The Epstein–Barr virus , also called human herpesvirus 4 , is a virus of the herpes family and is one of the most common viruses in humans. It is best known as the cause of infectious mononucleosis...
(EBV). After the primary EBV infection has been overcome, the virus stays latent in the B cell
B cell
B cells are lymphocytes that play a large role in the humoral immune response . The principal functions of B cells are to make antibodies against antigens, perform the role of antigen-presenting cells and eventually develop into memory B cells after activation by antigen interaction...
s and also causes lytic infection
Lytic cycle
The lytic cycle is one of the two cycles of viral reproduction, the other being the lysogenic cycle. The lytic cycle is typically considered the main method of viral replication, since it results in the destruction of the infected cell...
in the oropharynx
Oropharynx
The Oropharynx reaches from the Uvula to the level of the hyoid bone.It opens anteriorly, through the isthmus faucium, into the mouth, while in its lateral wall, between the two palatine arches, is the palatine tonsil....
, controlled by the immune system. Uncontrolled lytic infection in the oropharynx is manifested as oral hairy leukoplakia in immunosuppressed hosts. Oral hairy leukoplakia is not associated with any malignant
Malignant
Malignancy is the tendency of a medical condition, especially tumors, to become progressively worse and to potentially result in death. Malignancy in cancers is characterized by anaplasia, invasiveness, and metastasis...
potential.
In 1992, the University of Connecticut School of Dental Medicine reported on two cases of oral hairy leukoplakia occurring in patients without any risk factors for HIV infection, or any other evidence of immune deficiency. It has been observed in patients on steroid
Steroid
A steroid is a type of organic compound that contains a characteristic arrangement of four cycloalkane rings that are joined to each other. Examples of steroids include the dietary fat cholesterol, the sex hormones estradiol and testosterone, and the anti-inflammatory drug dexamethasone.The core...
therapy.