Cradle cap is the term used when seborrheic dermatitis affects the scalp of infants.
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.