The cause is unknown. Seborrheic dermatitis appears to run in families. Stress , fatigue , weather extremes, oily skin , infrequent shampoos or skin cleaning, skin disorders such as acne , obesity , and use of lotions that contain alcohol may increase the risk of seborrheic dermatitis. Neurologic conditions, including Parkinson's disease , head injury , and stroke can also be associated with seborrheic dermatitis. The AIDS complex or syndrome also seems to be associated with a higher incidence of seborrheic dermatitis.
Cradle cap appears as thick, crusty, yellow scales over the child's scalp.
Similar scales may also be found on the eyelids, ear, around the nose, and in the groin. Cradle cap may be seen in newborns and small children up to the age of 3 years. It is a chronic , recurring condition caused by inflammation of skin glands. It is similar to dandruff in adults. Cradle cap is not contagious, it is not caused by poor hygiene, it is not an allergy , and it is not dangerous.