Common signs and symptoms of dandruff include an unmistakable white, oily looking flakes of dead skin that dot your hair and shoulders and an itchy, scaling scalp. Your scalp can be either excessively dry or oily. Seborrheic dermatitis is a disease that causes flaking of the skin. It usually affects the scalp. In adolescents and adults, it is commonly called "dandruff." In babies, it is known as "cradle cap.