As a dentist I was always told in training that geographic tongue is a variation on normal anatomy, there is no known cause, no treatment indicated per se. But that if it was causing problems it is always worth investigating for the following:
- Haematinic deficiency (iron, folate, B12).
- Autoimmune disorders of the gastro intestinal system.
If these are not relevent, I would suggest the obvious, i.e. avoiding things that irritate it, good oral hygiene and an alcohol - free mouthwash (or hot salt water is also good).
A food and symptom diary is always a good place to start. I would also include your menstrual cycle in your data.
It is not associated with oral thrush. But just because you have geographic tongue does not mean you don't have oral thrush though, IYSWIM. Oral thrush is massively over diagnosed. In 11 years of practice I have not seen a single case. It is more likely to be seen in immunocompromised patients (think AIDS, leukaemia, chemotherapy), the very young infant (who I rarely see anyway), and the very elderly (I see lots and lots of these). The characteristic appearance is of a white cottage cheese - like lesion which can be scraped off (eg. with a finger nail or appropriate instrument) and leaves a raw bleeding surface. If you cannot scrape it off (like with the lighter parts of geographic tongue) or it doesn't bleed when scraped (like the white film you get with certain toothpastes) then it almost certainly is not thrush. There are other kinds of oral fungal infection, mostly painless. One is a condition only really seen in severe immuno compromise (mainly AIDS) and another only under dental appliance (dentures, orthodontic retainers, and cleft obturators) that are not kept clean enough, which are very distinctive.