If tissue biopsy is carried out, the histopathologic appearance is of hyperplastic and parakeratinized epithelium, with "balloon cells" (lightly staining cells) in the upper stratum spinosum and "nuclear beading" in the superficial layers (scattered cells with peripheral margination of chromatin and clear nuclei, created by displacement of chromatin to the peripheral nucleus by EBV replication). Candida usually is seen growing in the parakeratin layer, but there are no normal inflammatory reactions to this in the tissues. There is no dysplasia (OHL is not a premalignant lesion). Classification
In a classification of the oral lesions in HIV disease, OHL is grouped as "lesions strongly associated with HIV infection" (group I). It could also be classed as an opportunistic, viral disease. Hairy leukoplakia occurs on the tongue and has a similar name to hairy tongue, but these are separate conditions with different causes. Treatment
Treatment is not necessary since the lesion is benign, however, the person may have aesthetic concerns about the appearance. The condition often resolves rapidly with high dose acyclovir or desiclovir but recurs once this therapy is stopped, or as the underlying immunocompromise worsens. Topical use of podophyllum resin or retinoids has also been reported to produce temporary remission.Antiretroviral drugs such as zidovudine may be effective in producing a significant regression of OHL. Recurrence of the lesion may also signify that highly active antiretroviral therapy (HAART) is becoming ineffective. Prognosis
The oral lesion itself is benign and self-limiting, however this may not necessarily be the case for the underlying cause of immunocompromise.
Amino acid transport disorders are medical conditions associated with a failure of amino acids to be absorbed from the kidney or intestine. An example is Hartnup disease. Reference
External links

Milne MD (1971). "Disorders of intestinal amino-acid transport". J Clin Pathol. 5 (Suppl): 41–4. doi:10.1136/jcp.s3-5.1.41. PMC 1176258.