Dandruff is mostly due to the excessive Dryness or Oiliness that caused by increased secretion of sebum,Sweat .This may be in the form of Dry, whitish or yellowish flakes, powdery.Sometimes, skin c/o like Scalp psoriasis, scalp Eczema, Seborrhoeic dermatitis or Boils which cases exfoliation of skin layer after getting dried up are also could be thought of just Dandruff. Generally, in many types of skin diseases, there usually will be common symptoms like Itching, Irritation, dryness, or secretion of pus/ any other serous fluids, redness, exfoliation of skin, spreading[if caused by any bacteria, fungus]etc.Like that way, in dandruff also, there would be dryness, itching, irritation, based on severity, secondaries like formation of Acne[pimples] also may happen.
As precautionary measures, Always using the herbal shampoos[like containing Shikakai, Amla, Reetha , Hibiscus flowers, Brahmi, etc ]is good.At the same time, using Oils like coconut, Sesame, Oilve, Maize are good to keehair roots stronger& to maintain Scalp smooth.That application also should always be in gentle manner. Better to apply just 1-2 hrs before the head-wash. Try to wash hair weekly minimum 2-3 times, that too with soft-water, Avoid Hard water.
Coconut milk or water,Rice starch,Yoghurt with methi[soaked fenu greek seeds paste], vinegar with water, alovera will help to keep hair in good condition as well as to nourish the Scalp skin.
Diet also plays important role in keeping scalp healthy. So that, taking more water[minimum 3-4 ltr of water intake/day],taking of more raw vegetables, fresh fruit juices[with Honey mixed or with less sugar] or fruits as a whole, increasing the intake of more proteinaceous diet, whole wheat, whole grains, pulses, hand pounded rice, food that is rich in Vit A, E, B complex,& reducing the consumption of Sugar, Fat, canned, preserved food, junk food, etc followed by regular exercise, yoga, meditation which helps in keeping the mind stress free, will help in controlling as well as precautionary.
Always Better avoiding more chemical based Shampoos, conditioners, few cosmetic therapies like colouring, dying, straightening etc as these will result damaging gradually the hair as well as the scalp texture.
Homoeopathically, these conditions can be treated well, if u undergo T/t for a while. Medicines like, Calcarea carb, Graphitis, Lyco, China, Acid Flour,Acid phos, Phos, psorinum, Amm.Mur, Alumina, Sepia, Natrum mur, Thuja, Sulphur, etc will help, if were chosen according to individual’s symptom similarity.