Seborrheic dermatitis is a common skin condition that is similar to eczema and sometimes occurs in patients with eczema. In babies, it tends to mostly affect the scalp and is known as "cradle cap". Older children and adults can develop it on the scalp as well, which is similar to dandruff but tends to be more itchy and inflamed. It can also affect the face and upper chest in some cases, and can overlap with psoriasis.

The main symptoms of seborrheic dermatitis include one or more of the following:
Redness (erythema)
Itching
Dry and flaking skin
 
The cause of seborrheic dermatitis is thought to be due to an abnormal inflammatory response to a yeast normally found on the skin: Malassezia. Like eczema, many factors can aggravate seborrheic dermatitis including stress, change of seasons, illnesses, and heavy alcohol use, to name a few.