Dermatology MCQ - Viral Infections - Oral hairy leukoplakia

A 45-year-old man with poorly controlled HIV (CD4 count 180 cells/µL) presents with asymptomatic, white, corrugated plaques on the lateral borders of his tongue that cannot be scraped off. He is otherwise asymptomatic and has no history of smoking. Which of the following is the most likely causative agent and the best next step in management?

A) Candida albicans; initiate oral fluconazole
B) Epstein-Barr virus (EBV); optimize antiretroviral therapy
C) Human papillomavirus (HPV); topical imiquimod
D) Treponema pallidum; administer penicillin G
E) Lichen planus; topical corticosteroids

Correct Answer: B) Epstein-Barr virus (EBV); optimize antiretroviral therapy

Explanation

This presentation is classic for oral hairy leukoplakia (OHL), a condition strongly associated with immunosuppression, particularly HIV/AIDS.

Key Clinical Features of Oral Hairy Leukoplakia:

• Appearance: White, corrugated or "hairy" plaques with vertical striations, typically on the lateral borders of the tongue. Unlike candidiasis, these lesions cannot be scraped off.

• Symptoms: Usually asymptomatic (no pain or burning).

• Association: Almost exclusively seen in immunocompromised hosts, especially those with HIV (CD4 count <300 cells/µL), organ transplant recipients, or patients on immunosuppressive therapy.

Virologic and Pathogenic Features:

• Causative Agent: Epstein-Barr virus (EBV). OHL represents a lytic EBV replication in the epithelial cells of the tongue, facilitated by immunosuppression.

• Pathogenesis: Loss of immune control (especially cytotoxic T-cell function) allows EBV reactivation and hyperproliferation of keratinocytes.

Why Not the Other Options?

• (A) Candida albicans: Causes oral thrush, which presents as white, curd-like plaques that can be scraped off (leaving an erythematous base). It is often symptomatic (burning, discomfort).

• (C) Human papillomavirus (HPV): Causes squamous papillomas or verruca vulgaris, which are exophytic, cauliflower-like growths—not flat, corrugated plaques.

• (D) Treponema pallidum: Causes syphilitic mucous patches, which are silvery-gray erosions or plaques, but they are typically painful and associated with other signs of syphilis (e.g., rash, condylomata lata).

• (E) Lichen planus: Causes reticular or erosive oral lesions (Wickham's striae), which are often bilateral, symptomatic (painful or burning), and not exclusively on the lateral tongue.

Management:

• Optimize antiretroviral therapy (ART): This is the cornerstone of management. Immune reconstitution with ART often leads to resolution of OHL without specific antiviral treatment.

• Role of antivirals: If needed (e.g., for cosmetic reasons or discomfort), oral antivirals (e.g., acyclovir, valacyclovir) can suppress EBV replication and improve lesions, but they do not eradicate latent EBV.

• Avoid: Topical therapies (e.g., steroids, antifungals) are ineffective as the condition is viral and not inflammatory or fungal.

Prognosis:

• OHL is benign but serves as a clinical marker of significant immunosuppression.

• Resolution typically occurs with immune recovery (CD4 count >300 cells/µL).

• Rarely, it may be associated with an increased risk of EBV-related lymphomas in severely immunocompromised patients.

Differential Diagnosis:
Always rule out other causes of white oral lesions, especially oral candidiasis (scrapable) and premalignant leukoplakia (associated with tobacco use, and may be dysplastic).