Dandruff is a common scalp condition that causes flakes of dead skin to appear on the scalp and hair. It is not contagious or serious, but it can be embarrassing and difficult to treat.
The exact cause of dandruff is unknown, but it is thought to be caused by a combination of factors, including:
Malassezia globosa, a yeast that lives on the scalp
An overproduction of sebum, the scalp's natural oil
Dry skin
Sensitivity to hair care products
Skin conditions such as eczema and psoriasis
Dandruff can be worse in the winter when the air is dry and in the summer when the scalp sweats more. It can also be worse in people with stress or anxiety.
