When the part of skin is covered with rashes that are scaly, crusty and greasy then this condition is called seborrheic dermatitis in the terminology of medicine. However, in layman language, it is called cradle cap, crusta lacteal, milk crust, honeycomb disease etc. Though the affected area does not look good, this skin condition is not harmful. It does not irritate the baby and does not pose any threat to her health.
The reason behind cradle cap has not been discovered yet. This is probably because the disease is not harmful and vanishes automatically in course of time even without any serious medical treatment. However, the little research made to find out the causes behind cradle cap came out with different results. Some of the specialists opine that it is caused by the sebaceous glands in the skin of the baby. The reason why these glands are responsible is that the mother's hormones still work in the baby's circulation and the glands release a greasy substance.
This greasy substance make the old skin cells remain attach to the scalp when they try to dry and fall off. Others opine that cradle cap is caused by Malassezia furfur, a kind of skin yeasts. Specialists connected with nutritional orientation opine that it has something to do with immature digestive system of the baby. Whatever may be the case, the disease is not harmful and a little carefulness will suffice to keep it under control.