Causes

The cause of cradle cap isn't known. One contributing factor may be hormones that pass from the mother to the baby before birth. These hormones can cause too much production of oil (sebum) in the oil glands and hair follicles.

Another factor may be a yeast (fungus) called malassezia (mal-uh-SEE-zhuh) that grows in the sebum along with bacteria. Antifungal treatments, such as ketoconazole, are often effective, supporting the idea that yeast is a contributing factor.

Cradle cap isn't contagious, and it's not caused by poor hygiene.