I'm so glad you posted this message! I have folliculitis decalvans too, and for years have been dealing with low thyroid symptoms. However, my medical doctor said that my thyroid levels are normal; it was only a naturopathic doctor and an energy healer who detected anything wrong with my thyroid. Because my dermatologist wanted to put me on Antibiotics for 3-6 months or indefinitely, I decided to go the alternative medicine route and experiment with diet. The itchy stingy sensation on my scalp virtually disappeared after a month or two of being on the Paleo diet. I was told that once my immune system calms down, then I can reintroduce gradually and in small amounts some of the foods that I used to eat. Have you done that? I miss particularly eating beans and lentils, because I don't like eating meat all the time. Also, my naturopath said it's okay if I eat quinoa, buckwheat and brown rice, but those are the only grains. Are you eating any grains?
One other thing I find tricky is that because the condition progresses slowly it's hard to know whether I've arrested its spread or not. It's also hard to keep track of the symptoms because I can't see my own scalp! Anyway, I'm really glad that there seems to be other ways to manage this condition, and I'm now determined to deal more determinedly with my thyroid. Thanks for your post!