Cradle cap is not universal to all newborns, but it is surely very common. The term refers to a type of eczema, eczema of the scalp. The scalp is distinct as a patch of skin that makes much more oil than most other areas of skin. As a result, when the scalp gets inflamed with eczema, the rash includes oil, in this instance in the form of yellowish, often oily flakes. Typically, the eczema on the scalp of a newborn looks like a mat of whitish-yellowish sl oily flakes, hence the term cap.
The appearance of cradle cap is not worrisome, although lots of parents don’t like the look of it.
An effective response is to use baby oil and a brush. If you apply baby oil to your infant’s scalp at bedtime, the flakes that are so adherent will absorb the oil and loosen. The next morning, shampoo the scalp and with light brushing many or most of the cradle cap flakes will brush off. You can repeat as many nights as you like.