<prompt> In a patient having HIV infections, oral ulcer is most commonly due to -CandidaCryptococcosisHistoplasmaTrichophyton  <response>: Mouth often involved in AIDS with hairy leukoplakia or Kaposis sarcoma due to esophageal candidiasis It is also known as Oral thrush REF:ANANTHANARAYANAN TEXTBOOK OF MICROBIOLOGY 9EDITION PGNO.576 