<prompt> Cause of hairy leukoplakia which is characterised by severe discomfort on lateral part of the tongueHIVEBVHerpes virusHPV  <response>: B EBV Hairy leukoplakia is a distinctive oral lesion that is seen in immunocompromised patients. Approximately 80 of patients with hairy leukoplakia have been infected with the human immunodeficiency virus HIV; the presence of this lesion sometimes calls attention to the existence of the infection. Hairy leukoplakia takes the form of white, confluent patches of fluffy hairy hyperkeratotic thickenings, almost always situated on the lateral border of the tongue. The distinctive microscopic appearance consists of hyperparakeratosis and acanthosis with balloon cells in the upper spinous layer. 