And I'm wondering if the fungus could survive not being on your body and just on dead tissue. I'm also confused about the Psoriasis thing -- that's an autoimmune disorder, a form of arthritis, and it would be odd to only have symptoms on your head. It should also be able to be diagnosed as, again, this isn't just a skin disorder, it's an autoimmune disease. I would wonder about the fungus notion, as fungus needs a moist and protected environment to thrive, such as under toenails or around the groin or the feet where sweat is a regular factor. Not so much with the scalp. Whatever it is, when you get a lot of steroid and antibiotic treatments, including antifungals, it weakens the immune system and makes it a lot easier for other things to take root. It's possible the medication you had left you vulnerable, and rebuilding your immune system might be necessary. Probiotics are one way to do that, but just one part of it. Just a thought. Hope you find out what it is, and you really do need to see a dermatologist.