Seborrheic dermatitis/eczema is a form of eczema that can appear only on certain parts of the body. The appearance of the rash varies depending on the area of the body that is involved. On the scalp the rash typically appears red and scaly, whereas in the skin folds the rash is typically devoid of scale and therefore appears red and moist.
The typical areas of the body that can be involved by Seborrheic dermatitis are as follows:
- Scalp
- The skin fold behind the ears
- The skin fold between the nose and cheeks
- The ear canals
- The eyebrows
- The mid chest
- The mid back
- The groin area, including the skin folds between the upper legs and abdomen
Not all of these areas have to be involved and most often it is just the scalp areas.
The rash is generally not very itchy, but some people describe a burning sensation on the involved areas, especially the scalp. People that suffer from so-called “Dandruff” is frequently in fact suffering from Seborrheic dermatitis. Dandruff is not a medical diagnosis and refers to the small white skin flakes occurring on the scalp. There can be many reason for excessive flaking of the scalp, of which Seborrheic dermatitis is one.
Seborrheic dermatitis occurs in two separate age groups, before 1 year of age and after puberty. After puberty men tends to be affected more often than women.
Nobody really knows the cause of Seborrheic dermatitis, but the overgrowth of a certain organism called Pityrosporum ovale has been implicated. However, not all people with Seborrheic dermatitis have Pityrosporum ovale overgrowth. The finding of huge numbers of Pityrosporum ovale in areas of Seborrheic dermatitis might therefore be just the result of the Seborrheic dermatitis and not the cause of the Seborrheic dermatitis. Another theory about the cause of Seborrheic dermatitis is that Seborrheic dermatitis is a disease of skin overgrowth just like Psoriasis.
Another important association with Seborrheic dermatitis is infection with HIV. People with HIV tend to develop Seborrheic dermatitis when the suppression of their immune systems reaches a certain level.
The treatment of Seborrheic dermatitis involves the use of various shampoos containing one or more of the following ingredients: Zinc, Selenium, tar and anti-fungals. A corticosteroid containing lotion, cream or mouse can be used during a flare up. Recently Tacrolimus and Pimecrolimus has also been used successfully for the treatment of Seborrheic dermatitis.