Cradle cap (also called seborrheic dermatitis) is a rash that begins as scaling and redness on a baby's scalp. This condition is a noninfectious skin condition and is a form of eczema. Seborrheic dermatitis is common in infants, usually beginning in the first weeks of life and slowly disappearing over a period of weeks or months. The condition rarely is uncomfortable or itchy.

The precise cause of the rash is not known; however, Pityrosporum ovale (a yeast) is believed to play a role in this condition.