Seborrheic dermatitis is a common, chronic condition of skin which affects millions of people worldwide. It is a troublesome inflammatory skin condition which is not  fatal. Seborrheic dermatitis can affect different body areas such as the scalp, eyebrows, eyelids, creases of the nose, lips, behind the ears, in the outer ear, and middle of the chest. It tends to affect places where the skin is oily or greasy. In most cases the scalp is affected. [Read: What is Seborrheic Dermatitis?]

Common symptoms of seborrheic dermatitis are:
Yellowish-white scales and flakes on the scalp. The flakes may fall and are seen on shoulders of dark clothing—this is often the first symptom of dandruff. The scales and flakes may be waxy or greasy.
Dry itchy scalp, itch in the ear canal
Dry skin on face usually without any rash. It does not improve on application of lotions and creams. In fact it may become worse.
Yellowish-white, dry-looking, or thick, greasy scales on the eyebrows, sides of the nose, and behind the ears
Itch in ear canal and recurrent ear eczema.
Rash on eyebrows, nose, and ears. It may appear to be because of dry skin but application of moisturising creams and lotion may worsen it.
Oily scalp and facial skin with dry flakes.
Mild redness in the affected areas beneath the scales.
Dandruff on eyebrows or beard.
Rash on chest with dry flakes and red spots.

Cradle cap

It is the term used to indicate seborrheic dermatitis on scalp of infants. It is a harmless, temporary condition which improves in few weeks to months. Cradle cap is not contagious disease and it is not caused because of poor hygiene or allergy.

Signs and symptoms of cradle cap are:
Yellow, greasy scale on the scalp. It may be sparse and thin or a thick layer of scale can be present over the entire scalp. Scale may be yellow to brownish in colour. The scale becomes flaky and fall off in a few weeks to months (with or without treatment). Rarely cradle cap may be present till the age of 3. Other areas that can be affected by seborrheic dermatitis in infants are the face, usually on a baby’s eyelids, around the nose, or ears. In some infants it may appear on diaper area and rarely seborrheic dermatitis may cover most of the body of an infant.