Posted by Ted (Bangkok, Thailand)
Hydrogen peroxide/apple cider vinegar might help in removing the source of dermatitis. Apply that first, wait for a couple of minutes, then rinse. This is then followed by a generous application tea tree oil to the entire scalp. Wipe of the excess, leave it overnight. Based on my own personal experience, one application does it. If it comes back in a couple of months, redo the above. Dandruff should go away in 2-3 days.
Recipe using Apple Cider Vinegar and Hydrogen Peroxide: Dilute them by 1:10: 1 part ACV, 1 part Hydrogen Peroxide with 10 parts water. Use like a shampoo and rinse after the shampoo is "finished" to make the cure for scalp infections even more potent.
Leave the mixed solution on scalp for about one minute before rinsing away in water. Repeat this again if the infection is severe enough. Avoid getting the solution in the eyes as it may cause stinging. You do not need large amounts of the concoction, only small amounts... just enough to get it to the scalp.
Again, it seems to work with remarkable consistency. For some reason, I found using shampoo as the cause of dandruff. I don't know what they put in. However, an easy way to test it is do apply it on your skin to see if you have a skin reaction, after applying the pure shampoo over the arms for a couple of hours.
If you want to permanently reduce the problems of shampoo caused dandruff, the addition of small amounts of sodium thiosulfate and tea tree oil and lavender oil to a non fragranced shampoo will solve most of the problems. I now make my own shampoo for my mother and sister due to brand name shampoo causing severe itchiness and dandruff. This formula seems to work very well and never had any problems. One application, strangely is all you need. Perhaps severe dandruff might need 2-3 applications.
If the problems persist use aloe vera oil and tea tree oil apply to scalp. This is done only once. Aloe vera oil will heal the scalp.
Take lots of vitamin C for a week. This will also help healing.
One of the causes of scalp problems is inability for body to absorb vitamin A. It's been my experience that people with scalp problems not drink or eat fresh carrot juice as often (usually never!) and this will help the body absorbed the needed vitamin A. Synthetic vitamin A, even natural ones they sell in supermarkets don't seem to work.
There is a lot of misunderstandings in the use of aloe vera in the use of severe dandruff. The ONLY aloe vera that I found useful in dandruff is ALOE VERA OIL. But aloe vera oil alone is not effective unless when mixed with tea tree oil AND/OR lavender. If you are desperate (seems you are) use pure tea tree oil and apply it throughout your head - soaked. Do this for three days in the row. If it doesn't work, then complain!
Another little known information is that I found many people who DON'T DRINK enough water (avoid count tea, coffee, coke, beer) have severe dandruff. Sometime ago, I told some colleague as a passing remark to drink 0.5 liter in the morning before breakfast, 0.5 liter of water before lunch, 0.5 liter of water before dinner, and 0.5 liter of water before sleep. (Water must be dechlorinated). What was so amazing was persistent skin peeling (which lasted years) and dandruff stopped within a week. Recently I had this problem myself - horrible facial skin peeling for months and cured myself after finding my urine conductivity exceeded 90,000 siemens (heathy levels is about 40,000). So excess blood salinity could possibily be another cause. Excess salinity causes cellular dehydration, which in turn causes skin scaling, in my case facial skin peeling, in your case possibly severe dandruff.
Avoid absolutely the use of all shampoos. Use only a very mild soap to shampoo your hair. Salts in shampoos contributes to dandruff - which again causes scalp dehydration. Follow this by putting borax to saturation to the water and wash your hair, then rinse. Borax have antifungal and antiparasitic properties.
You need not do frequent shampooing of hair. Just do enough. This is then followed by apple cider vinegar and small amounts of common drug store 3% hydrogen peroxide mixed to it(if you are that desperate). These severe dandruff are usually fungus, which is why the treatment is so detailed. Fungus is really difficult to get rid of, but it was not a problem down here in Bangkok.
The small amounts of 3% hydrogen peroxide can be added a bit to apple cider vinegar. Since this is used only externally, you won't have trouble finding the hydrogen peroxide. Just get the 3% hydrogen peroxide they use at drug stores.
Once your hair is all dried and everything, before going to sleep, apply pure tea tree oil. If not, add some 50/50 with aloe vera oil, if you find it too strong. However aloe vera oil need not be applied for everyday. You need to apply it for only once a month, if need be. Again, these procedures more or less cured my friend of a severe dandruff problems. The tea tree to effect a reduced visible dandruff, was effective after 1-3 applications (1-3 days). Actually, I was satisfied with just one application, and it was manageable after that. You need to follow this by a maintenance dose of this (usually just tea tree and some alo e vera oil would do it) once a month.
Apple cider vinegar is needed to remove scaling of dandruff, but for maintenance - monthly or weekly, just apple cider vinegar, tea tree and aloe oil might do. Aloe vera oil is used only once every 2 weeks or a month. You don't need to use it that often and it is always mixed with tea tree oil and sometimes in combination with lavender oil - in case tea tree were a bit too irritating.
If you are STILL having problems, consider taking internally a peroxide form of colloidal silver. The procedure is simple. Buy any colloidal silver, add one drop of 3% food grade hydrogen peroxide and take it 1-3 tablespoon/day. Again, this is not needed now, and I know you will have trouble finding them. We will discuss this later.
Again, if YOU ARE STILL HAVING problems, eat one large onion a day - in salads or sardines (mixed with lemon) And add this onion juice to shampoo your head. Dandruff is a sulfur deficiency and my grandmother used onions to cure dandruff. I used onions - amazing stuff - to cure my hypoglycemia conditions. Onions lowers (or suppresses) blood glucose helps with dandruff condition by allowing normalization of cellular metabolism, instead of cellular death, which causes dandruff.
I hope this helps! If not, send me another feedback. There are other methods that will work also, but I have so little information regarding your health (pH, salinity, etc.) that I am generalizing these treatments.