Cradle cap is a patch of greasy, yellow-tan scales or flakes on a baby's scalp. It is not painful for the baby and is completely harmless. Many babies have mild cradle cap. Occasionally a baby will have such severe cradle cap that it covers most of the head, causing "cradle helmet."
Cradle cap is a side effect of the mother's hormones. During a pregnancy, the mother's body produces high levels of hormones. These cross into the unborn baby's body as well. After the baby is born, the leftover hormones make the baby's skin secrete sebum, the oily yellow material which causes cradle cap.
Besides cradle cap, mother's hormones can cause other harmless skin conditions like newborn acne.
Most lotions and creams don't help cradle cap. We recommend use of a selenium-containing shampoo, such as Selsun Blue. Here's how we like to do it: