Help finding a cure for dandruff/ seborrheic dermatitis on the scalp...

I have had a lifelong struggle. The itching is insane, no matter what method I have tried from shampooing every other day, not shampooing for a while, every day, every type of medicated shampoo out there.  Vinegar, clay, witch hazel, egg, lemon balm, tea tree oil, baking soda, salt.  Nothing works.  Except being at the beach, then it clears up after swimming in the ocean.  But salt water rinses do nothing.  I am thinking there must be an organic way to help solve this issue. Even if I cannot cure it, to keep it maintained. It has made my quality of life so very low. And even if I find a thing or two, that might work, if I miss even a day it goes right back to the misery.   Seeking help with a life long problem, any advice at all I will greatly appreciate.  I'm wanting a plant/ herbal/ or natural remedy.. do not want to spend the rest of my life going to a doctor or dermatologist to try to maintain.

Could it be your water? I've struggled with it before, though not as badly, and I notice that different water can affect me at different times. The water at my in laws always leaves me so itchy and sore. The water at home is usually OK, but when I'm having a flare up it's also irritating, so I use rainwater or distilled water from our dehumidifier until it's settled.

So it could be that some of the cures you've tried would be effective if combined with different water.

The only other suggestion is raw milk. I haven't actually tried it on my hair, but it does wonders on the dermatitis on my hands.

Sometimes dandruff is caused by dry skin on the scalp.  Are you sure it is dandruff and not dry skin?  and those treatments you used are not for dry skin.

As Ali suggested it could be your water.

My water is alkaline and causes dry skin.

Or it might be the brand of shampoo.  Try one for dry skin or try going pooless (without shampoo) and using bottled water.

For me, a 96% solutions was to go poo-less.  

Next step - while on a different health journey it was suggested that dandruff is caused by what you eat.  

And the last bit, again, for a different thing, it was suggested that I needed to have more minerals through the skin.  Castor oil topically was suggested.  The idea was that i would absorb minerals and the like at night.  But man that stuff is sticky.  So - no way.  .... until i got this little cotton sleep hat.  https://amzn.to/3QlCZL8  - i put the oil on my noggin, cover with the hat and wake up with horrible bed head.    It does seem like the oil is 90% gone in the morning.  And a poo-less shower seems to take a bit more away.      Da oil https://amzn.to/3QlCZL8     I might do this every week or two.  My guess is that at some point i will stop completely.

Zero danders.

Mostly, I enjoy not smearing the dandruff shampoo goo on my head - even the highest quality stuff struck me as toxic.  It has been more than 15 years now.  I feel like it is one of the smartest things i have ever done.  

I also like that my daily shower is about a minute long rather than ten minutes long.  

The idea of ever using shampoo feels brutally unhealthy.  My current path feels extremely healthy.  I am so glad i made the change.  

I will even go so far to say:   i wonder if the anti-dandruff shampoos actually CAUSE dandruff!