Hairy leukoplakia (HL) is a condition that results in the formation of white patches inside the mouth, most commonly found along the sides of the tongue. Despite its name, the lesions do not involve actual hair, but instead have a fuzzy or “hairy” appearance due to their distinct surface texture. This condition is generally classified as a non-cancerous lesion, meaning it does not carry the risk of transforming into oral cancer. While not a disease on its own, its presence often serves as an indicator of an underlying issue with the body’s immune system.
Appearance and Key Characteristics
The defining feature of hairy leukoplakia is the development of white, raised plaques that have a corrugated or folded texture. This shaggy surface, created by an overproduction of keratin, gives the lesion its characteristic “hairy” or feathery look. These patches are predominantly located on the sides of the tongue, although they can sometimes appear on the floor of the mouth or the cheek lining.
These white patches are firmly attached to the tissue and cannot be scraped off. The patches can range in size from small, faint white streaks to larger, more prominent lesions with noticeable folds and projections. Hairy leukoplakia is asymptomatic, meaning it causes no pain, so patients are often unaware of its presence until it is noticed during a routine oral examination.
Underlying Cause and Associated Risk Factors
Hairy leukoplakia is caused by the reactivation and productive replication of the Epstein-Barr Virus (EBV) within the cells of the oral lining. EBV is a highly common human herpesvirus that infects the majority of the population worldwide, usually remaining dormant after the initial infection. The virus remains hidden within the body’s B lymphocytes for life, but a healthy immune system keeps it suppressed and inactive.
The development of HL signifies a significantly weakened immune system, allowing the virus to multiply rapidly in the superficial layers of the tongue’s epithelium. Therefore, the primary risk factor for HL is severe immunosuppression. The condition is strongly associated with Human Immunodeficiency Virus (HIV) infection, particularly in individuals whose disease is progressing or whose treatment is failing.
The condition is not exclusive to HIV-infected individuals and can also be seen in other groups with compromised immunity. The appearance of HL can often be an important early indicator of a compromised immune status that requires medical attention.
At-Risk Groups
- Organ transplant recipients who take powerful immunosuppressive medications to prevent rejection.
- Patients undergoing chemotherapy.
- Those with other severe immune disorders.
- Individuals using inhaled steroids for respiratory conditions.
Diagnosis and Differentiation
A health professional can often diagnose hairy leukoplakia based on a clinical examination of its appearance and location. The characteristic fuzzy, non-removable white plaque on the lateral tongue is highly suggestive of the condition, especially in a patient with known or suspected immune deficiency. Diagnosis relies heavily on differentiating HL from other common white lesions that occur in the mouth.
For example, oral thrush (candidiasis), a fungal infection that is also common in immunosuppressed individuals, can appear as creamy white patches. Unlike HL, oral thrush lesions can usually be wiped away, revealing a red, inflamed surface underneath. It is also important to distinguish HL from traditional leukoplakia, which is a white patch that cannot be scraped off and is often linked to tobacco use and carries a small risk of becoming cancerous.
To confirm a diagnosis, especially when the appearance is not typical, a doctor may perform an oral brush biopsy or a small excisional biopsy. Laboratory tests can be conducted on a tissue sample to detect the presence of EBV DNA or EBV-encoded proteins within the lesion’s epithelial cells. This virologic confirmation provides a conclusive diagnosis that the white patch is hairy leukoplakia.
Management and Treatment Options
Treatment for hairy leukoplakia is often unnecessary because the lesion is benign and painless, posing no risk of malignant transformation. If the patches are small and not causing cosmetic or functional discomfort, no specific treatment is recommended for the lesion itself. However, the presence of HL signals the need to address the underlying cause of the weakened immune system.
For individuals with HIV, the most effective “treatment” for HL is the initiation or optimization of highly active antiretroviral therapy (HAART). Successfully managing the HIV infection and boosting the body’s overall immunity often leads to the spontaneous resolution or significant regression of the hairy leukoplakia lesions. When treatment of the lesion is desired, typically for cosmetic reasons or if the patient experiences mild discomfort, antiviral medications such as acyclovir or valacyclovir can be prescribed.
These antiviral drugs work by inhibiting the replication of the EBV, which often causes the lesions to fade or disappear quickly. However, the lesions frequently return once the course of antiviral medication is stopped, unless the underlying immune suppression has been resolved. Topical treatments, such as podophyllum resin, can also be applied directly to the patches, but these offer a temporary solution, and the condition is not permanently cured by treating the lesion alone.