A rare case of hairy leukoplakia in a young immunocompetent patient.

We present a case of oral hairy leukoplakia (OHL) in a male, 21-year-old immunocompetent patient. The patient had white, asymptomatic plaques located bilaterally on the tongue margin. The patient noticed the signs days after burning his tongue with hot food, which triggered the investigation. The case was treated initially as candidiasis and frictional keratosis. Exfoliative cytology indicated the presence of actinomycetes in the lesions, and a blood count suggested mild leukopenia (3,910/mm³; reference value 4,500 - 11,000/mm³). Photodynamic therapy and antiseptic mouthwash were used, with no improvement in the condition. The diagnosis of OHL had concluded after an incisional biopsy and immunohistochemical examination for anti-EBV. The patient's blood and serological tests showed no noteworthy changes. Cases of hairy leukoplakia in immunocompetent patients had founded in the literature and suggest that when this occurs, patients often have some comorbidity, such as hypertension, or use medications such as antihypertensives and steroid inhalers. However, the patient in the present case did not any of these conditions, which made the diagnosis challenging. In any case, it is always important to investigate the medical history and immune status of a patient diagnosed with OHL.