normally you treat it with good old canesten :) You can get a tablet to take, or you can use a combo of a pessary and cream for the external itching. if you're a bit strapped for cash though, live yoghurt should do the trick too, but you have to make sure it's the stuff with live bacteria in it, a pot of Muller light won't do the business
Thrush is a bacterial infection that can be cause be basically not having enough ventilation down there. Synthetic pants and tight trousers are a no no if you are trying to get rid of it, cotton knickers and baggy trousers till it's gone thank you please :)