Dandruff is a disorder of the scalp that causes itching and flaking. The Mayo Clinic says the condition is common and is not serious. But it can be embarrassing. The good news is that it’s usually treatable, especially if your dandruff stems from one of the most common causes of the disorder.
Plain old dry skin is the No. 1 cause of dandruff, according to the Mayo Clinic. This most commonly occurs during winter, when the air is dry, especially in heated homes. Using a moisturizing shampoo or an over-the-counter dandruff shampoo can help clear up dandruff caused by dry skin.
It may seem a bit counterintuitive, but oily skin also is a common cause of dandruff. Not shampooing your hair often enough can cause oil and skin cells to build up, which in turn causes dandruff. A more likely cause is a condition called seborrheic dermatitis. Look for red, greasy skin covered by white or yellow flakes. You can usually treat this condition with over-the-counter dandruff shampoos, but severe cases may require a prescription medication, according to the National Institutes of Health.
Although dry skin and seborrheic dermatitis account for most cases of dandruff, a few other conditions can cause dandruff. The Mayo Clinic says skin diseases such as eczema and psoriasis can infest the scalp and cause the skin to flake off. You might also get dandruff from a fungus called malassezia that lives on the scalp of most people and usually doesn’t cause any problems. Sometimes the fungus grows out of control, in which case it irritates the skin and causes more cells to grow. When they die, they slough off, leaving flakes in your hair and clothing. Another possible cause is a skin reaction to hair-care products, according to the Mayo Clinic.