Thrush and oral lichen planus can easily be confused. Lichen planus is an auto-immune disease and there is no cure... only treatment for the symptoms. I have had lichen planus for about 8 years now. It began on the skin on my legs, feet and chest but I didn't get it diagnosed until I had a few bouts of what I thought was thrush. My dermatologist diagnosed it with a skin biopsy on my chest - he didn't want me to have to have a mouth biopsy. He then referred me to a dentist 60 miles away who was especially interested in and experienced in treating oral lichen planus. He recognized what it was immediately and prescribed a special "rinse and spit" elixir of nystatin and dexamethasone, which I had to use severeal times daily for 2 minutes. It is can be brought on by stress if you are predisposed to it. Also by trauma to the mouth tissue, such as eating things that can scratch your cheeks like chips, hot and spicey things, or eating hard candies a lot. Once you have it you're stuck with it.... it will come and go but does last for very long periods each time. I have been free . My doctor has also prescribed a 2% lidocaine viscous solution that I can use on my tongue or cheeks that enables me to eat comfortably when it is particularly painful.
In my case, I was predisposed to this by hepatitis C for which I had been successfully treated for a year. It was shortly after I finished the treatment that I began having the symptoms of LP. It's not pleasant, but it is manageable and it can be kept under control. I can understand it being mistaken for thrush, because it feels much the same, but LP is visibly distinguishable to a doctor or dentist.
Good luck and see if your doctor will consider giving you the "magic mouthrinse". Let me know how you do....... Karen
Just wanted to apologize for the error in the first paragraph of my response. I started to say that I have been free of symptoms for probably a year or more until just this week. I don't know what happened to the rest of the sentence.....