I dont know, but I would suggest you try Nizoral shampoo. You can also rinse your hair after your shower with about a tablespoon of white vinegar in a basin of cool water. I'd suggest washing the sink out with baking soda and water or vinegar to get the sink clean before putting the water in.
Hello,
The exact cause of seborrheic dermatitis is not properly understood and the prime cause is thought to be an yeast (fungus) called Malassezia. Although it is a fungus, but unlike other fungal infections, it is not contagious and is not considered an infection. Hence it is not transferred to the other people, towels, beddings etc.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.