The term "cradle cap" is used very differently and has only a colloquial meaning for an undefined, scaly or even scaly-crusted rash. Especially in infants or toddlers, chronic, scaly rashes on the face or hairy head (see Crusta lactea) are called "milk crust".
Milk crust is often equated with the early manifestation of atopic eczema (colloquially - neurodermatitis), but this is by no means justified as other eczema diseases (e.g. seborrhoeic eczema) can also appear under the clinical picture of milk crust.