What is it?
This is chronic inflammation of the skin that arises in genetically predisposed individuals. The rash characteristic of the disease occur mainly in areas of increased production of oil (sebum) by the sebaceous glands.
The cause of seborrheic dermatitis is unknown but the excessive seborrhoea and a fungus (Pityrosporum ovale) present in the affected skin are involved. The highest activity of the sebaceous glands occurs under the action of androgenic steroids, so the onset of symptoms usually occurs after puberty. The neonate may also present manifestations of the disease due to maternal androgens.
Characteristics and symptoms
Seborrheic dermatitis is chronic, prone to periods of improvement and worsening. The disease is usually worse in winter and in situations of fatigue or emotional stress.
The manifestations frequently occur on the scalp and are characterized by intense production of sebum (seborrhoea), scaling (dandruff) and pruritus (itching). Dandruff can vary from fine scales to large crusts adhered to the scalp. The itching, which may be severe, is a common symptom in this region and may also be present to a lesser extent in other locations.
When they reach the skin, the lesions of seborrheic dermatitis are reddish and present greasy scaling. The areas most affected are the face (especially the nasal contour, eyebrows and forehead), ears, retroauricular region and the center of the anterior and posterior thoracic region.
Other manifestations are seborrheic blepharitis, which affects the eyelids, and the presence of lesions in areas of skin folds, such as the armpits and inframammary regions. Severe cases of seborrheic dermatitis can progress to widespread lesions, affecting large areas of skin.
There is no medication that will end definitively with seborrheic dermatitis but its symptoms can be controlled. In some people, greasy foods, alcoholic beverages and hot baths may worsen the condition, and should be avoided.
Treatment is usually done with local use of medications in the form of soaps, shampoos, lotions or creams that contain corticosteroids or anti-fungal drugs, among other components. In very severe cases, oral medications may be used. The appropriate treatment depends on the location of lesions and intensity of symptoms, and should be indicated by a dermatologist.
- Contact dermatitis