Within a few weeks of being born, some babies develop redness and greasy, yellow patches or scales on their scalps. Don't worry if this happens to your infant. It is called cradle cap and is neither an allergic response to what you've given your baby nor is it because of poor hygiene. It is called dermatitis seborrhoeica neonatorum and usually disappears within a matter of weeks or months.
Cradle cap won't bother your baby, unless it is compounded by the development of a yeast infection on top, which can be quite itchy. The redness and scales can appear elsewhere on your baby - for example on the buttocks, in the creases of the neck, in the armpits, and groing, as well as on the eyelids and behind the ears (that is, wherever the most oil glands, also called sebaceous, are located).
No one is sure what causes cradle cap, although it's clear that there is probably a link to pregnancy-related hormones, which stimulate sebaceous glands.
Cradle cap is easy to recognize by its greasy scales. If you are in doubt, check with your pharmacist, who is there to help you.
You can treat your baby's cradle cap at home with gentle shampoo only. To loosen the scales, brush the head gently with a soft baby brush or damp washcloth. Then shampoo the baby's scalp and rinse carefully. It can be helpful to rub a little mineral oil or olive oil on the scalp about an hour ahead to loosen the crusty scales. Work gently, especially around the baby's soft spot, or fontanelle, and be careful not to break the skin.
If shampooing doesn't improve the condition, or if the cradle cap is spreading, your baby's doctor may suggest a topical cream or a special medicated shampoo.
If cradle cap worsens and the baby is fretting, it may be that a yeast infection has developed and an anti-yeast medication may be required. See your pharmacist or doctor who will recommend what's necessary.