Cradle cap is a skin condition that many children get at some point during their first five years. It's especially common in babies less than one year old (thus the cradle part) and often appears on the scalp (the cap part), although it can occur on other parts of the body as well.
The technical name for cradle cap is infantile seborrheic dermatitis. Adults can also get a form of seborrheic dermatitis.
Cradle cap does not harm your baby or cause them discomfort. It's also not contagious for either children or adults.