If the problem is very severe you should seek advice from the doctor as a course on steroid's may be required to clear it up. Seborrhoeic appears to be heredity, if some relative has it the chances are that is what you may have. It is not contagious but can be passed on through the family. It is usually seen as silvery flaky scales on the scalp or anywhere on the body. The more serious cases of psoriasis should be referred to a doctor for treatment.
Doctors often prescribe steroid creams to help cure the problem.
People have recently been praising the use of evening primrose oil to try and treat the problem. Women taking this as a daily supplement have reported excellent improvement in their skin as well as in their general well being. Old Cures Boric acid is a very old remedy for treating dandruff, and is freely available from your chemist. Moisten with a little water and rub well into the scalp, then rinse out thoroughly with warm water. This should be carried out just before you shampoo your hair in the normal way.