Opportunistic activity by combinations of otherwise normal bacterial flora, such as aerobic streptococci, Neisseria , Actinomyces , spirochetes, and Bacteroides species can prolong the ulcerative process. Fungal causes include Coccidioides immitis ( valley fever ), Cryptococcus neoformans ( cryptococcosis ), and Blastomyces dermatitidis ("North American Blastomycosis ").  Entamoeba histolytica , a parasitic protozoan , is sometimes known to cause mouth ulcers through formation of cysts . [ citation needed ]
For 18 months I saw dentists, oral surgeons, family doctors, ENT’s, and emergency medicine doctors (both in the USA and the UK). They all called it ‘burning mouth syndrome’ and prescribed antibiotics, mouthwashes and anti-fungal creams. After begging for a biopsy, I got the call – it was cancer. I had surgery on my tongue but no chemo, radiation or neck dissection was needed. It was 2005. In 2010, I had pain in the same area which was dysplasia and they performed laser surgery on the same spot to ensure they got it all. In 2012, I had the same complaint of pain and a new spot. Dysplasia was diagnosed again but required no further treatment. Two months later, I complained of a spot and discomfort. They lasered it again. We need more time and attention devoted to oral cancer research. My story is not over!