Sebhoric dermatitis a common skin condition that mainly affects your scalp. It causes scaly patches, red skin and stubborn dandruff. Seborrheic dermatitis can also affect oily areas of the body, such as the face, upper chest And back Symptoms:: 1)Skin flakes (dandruff) on your scalp, hair, eyebrows, beard or mustache 2)Patches of greasy skin covered with flaky white or yellow scales or crust on the scalp, ears, face, chest, armpits, scrotum or other parts of the body 3)Red skin