Dandruff is not something that you can catch from someone else. It is an embarrassing condition but also a major cause for hairfall and hair weakening. It is estimated to affect as many as one in five individuals in India. You’re said to suffer from the problem of dandruff when the skin renewal cycle of your scalp accelerates all of a sudden. This brings about the development of patches of dead skin on your scalp surface and the resultant dry, skin flakes called dandruff.
The causes of this very common problem can be:

• Having dry skin can also cause dandruff to develop, which are less oily and smaller in nature.
• Even irritated oily skin, more commonly known as seborrheic dermatitis can cause you to suffer from these white skin flakes. The problem can be easily identified by its distinguishing yellow or white flakes over the red greasy skin surface.
• Not shampooing your hair regularly can cause skin cells and oils to build up in the scalp leading to the outbreak of dandruff.
• Sensitivity to certain hair care products and the presence of Malassezia (a type of fungus) are other causes that can lead to dandruff problems.

Oiling your hair is the most effective measure that you can take against this scalp problem. While the ideal time to do this is at night so that you can wash it off the next morning, one should also remember that hair oil shouldn’t be left on the hair for over 24 hours. Additionally, dry scalp makes it very easy for dandruff to develop as the oil-secreting glands found in the scalp’s epidermal layers produce low or no natural oil. Application of oil helps in keeping the scalp nourished as well as enables glands to produce oil. But leaving it on for more than the recommended hours can intensify your dandruff problem and further accelerate the hair fall process.

Ref : Lybrate