Dandruff and cradle cap are common names for seborrheic dermatitis. Babies 3 months and younger often get cradle cap: crusty yellow or brown scales on their scalp. It usually goes away before they're a year old, although it can come back when they reach puberty. You might get seborrheic dermatitis on your face, especially around your nose, on your eyelids, or behind your ears. It can show up on your body, too:

In the middle part of the chest
Around the navel
On buttocks
In skin folds under arms and on legs
In the groin
Below breasts

On babies, seborrheic dermatitis might be mistaken for diaper rash. Skin can itch, burn, or look red. The scales that flake off could be white or yellowish and look moist or oily. Because it can look like other skin conditions, you should see a dermatologist (a doctor who specializes in skin problems) to get a diagnosis and the right treatment. The dermatologist will ask about your medical history and look at your skin. You may need other tests if the doctor thinks it's related to another medical condition.