For years I tried everything to cure my scalp SD, including borax, ACV, oils. Nothing worked. Digging deeper as now it started to translate into the beginnings of hair loss, I found it had to be Malassezia and that the only promising treatment for that was zinc pyrothione. Bought some on ebay (hard to find, but I wanted the pure version, without alcohol), diluted it down to about 1%, and put it in my hair for a few minutes before rinsing. It actually works. When I comb my hear with my hands, I would always have strands of hair in them - 'normal', as the hair tends to grow back - but now, I can barely pull a single hair. It's pretty amazing. They tell you it's normal to shed hundreds of hair every day.
Honey, Peroxide, Zinc Pyrithione
If you have a diagnosis of SD you will know that there are many sites that say it is caused by Pitisporum Ovale, they are incorrect. SD is caused by Malassezia Globosa. My eight year old had it all over his face and it was spreading rapidly, the doctor gave us a prescription for Eldel, which has a black box warning and was $40+ even with insurance. It surpresses the immune system and I would not use it on my child who is a cancer survivor. My poor son could not tolerate any of the antifungals I put on his face, his skin was extremely sensitive and everything was painful. I finally hit upon non-pasturized honey, it works. Cleanse the area with hydrogen peroxide, put honey on all the areas. I put it on him right after school and then re-applied at bedtime. I also read a study that zinc pyrithione kills Malassezia Globosa, so I also purchased a 1% zinc pyrithione spray called "Z Care" by supplement spot.com on the net. It took forever for them to ship it, but it works. Once you know the exact cause, you have a better chance of fighting what ever it it is. My son could not tolerate head and shoulders on his face whatsover, but the "Z care" spray doesn't burn as long as you wait 10 min after you wash your face. Results with the honey alone were visibile in a day or two, but it is slow going until every little flaky area is gone. It took about 2 months to completely heal him. A note of caution, if the SD is all around the nose area, consider applying the honey and the zinc pyrithione carefully to the inner rims of of the nostrils. I just use a q-tip to appply anything to his face anyway. Don't spray the spray near your face, spray the Q-tip first. The SD was so bad that he also developed a secondary staph infection on the side of his mouth. The honey healed it, and knocked the infection right out. He has a small pink area of scar tissue, where the staph infection was, but I am hopeful this will fade with time.
Read the study: http://www.pgbeautyscience.com/defining-issues.html