Cradle cap, or seborrheic dermatitis, occurs in most infants during the first few months of life. It is a crusty, oily build up that appears on the scalp, with an underlying redness and irritation. It can extend down onto the face, the neck, and the upper chest. It is analogous to adult dandruff. It is thought to be caused by a combination of oily skin, hormonal effects, and occasionally fungus growth. It can fluctuate in severity from day to day, sometimes appearing mild, and sometimes flaring up into angry, red, bumps and pimples.

Treating cradle cap - for the scalp and eyebrows, you can massage in olive oil or baby oil, then gently comb or brush out the flakes. This isn't a cure, however, and the crusts generally keep building back up again for the whole first year of life. You can get rid of cradle cap once and for all using dandruff shampoo (either a selenium or a tar based shampoo is fine) twice a week for several weeks. You can decrease the frequency as the condition improves. You may need to use it once a month or so to keep the "dandruff" away.

Treating seborrhea on the face and skin - you can use an over-the-counter extra-strength hydrocortisone cream once or twice a day for several days at a time to minimize the rash. This isn't a cure, however. It will just keep it in check until the condition naturally goes away.