Dandruff is a common condition that is associated with excessive flaking of the scalp. This condition can cause itching and redness of the scalp and is usually uncomfortable for people. There are several reasons that can cause dandruff, including:

Dry scalp: One of the most common causes of dandruff is a dry scalp. Cold winter weather and the use of heating systems can aggravate this condition.
Oily scalp: An oily scalp attracts dust and other environmental factors that can lead to dandruff.
Malassezia fungus: This fungus lives naturally on the scalp, but in some cases it can grow excessively and cause dandruff.
Allergy to hair care products: Some people may be allergic to certain products, such as shampoos or hair dyes, which can lead to dandruff.
Insufficient washing of hair: Insufficient washing of hair can cause a buildup of dead skin cells and oil, resulting in dandruff.