Seborrheic dermatitis is a chronic inflammatory skin disease, recognizable by red patches covered with white or yellowish scales on the face or scalp. Evolving in successive flare-ups, this disease can occur in infancy and continues into old age. After a clinical diagnosis, the treatment combines different local drugs. Appropriate daily care can also prevent flare-ups.

What is seborrheic dermatitis?

Seborrheic dermatitis, is an inflammatory skin disease (or dermatosis) characterized by the presence of erythematous (red) patches covered with fatty scales.

These lesions develop in areas where the secretion of sebum is the most important (called "fatty" or "seborrheic"), for example:

The scalp ;

The furrow between the nose and the cheeks or the lips;

The eyebrows and the space between them.

It is a benign disease and not contagious, but chronic; it progresses by relapsing attacks. Because of the apparent nature of the lesions, seborrheic dermatitis has an impact on the quality of life.

What causes seborrheic dermatitis?

Seborrheic dermatitis occurs when the scalp cell renewal process is shortened. This leads to rapid separation of cells from the stratum corneum of the skin, which stick together to form visible flakes. This process can be linked to several causes. Seborrheic dermatitis is inherited; children of people who have it are more likely to contract it. However, this disease has also been linked to irritation of a yeast infection called Malassezia which thrives in very oily areas of the skin. It causes micro-inflammations which cause itching of the skin and scalp.

Other factors such as physical or emotional stress, hormonal changes, poor diet, alcohol consumption, fatigue, extreme weather events, infrequent use of shampoo, improper cleansing of the skin, and obesity can increase your risk.

Neurological diseases, such as Parkinson's disease, head injuries, and stroke may be associated with seborrheic dermatitis. HIV has also been linked to an increase in cases of seborrheic dermatitis.

Symptoms of seborrheic dermatitis:

Seborrheic dermatitis develops gradually and progresses in successive flares, the frequency of which can vary greatly from person to person. The main clinical signs include:

The appearance of red patches in certain seborrheic areas of the skin;

The development of white to yellowish dandruff or scales;

Sometimes itching and a burning sensation, especially in the scalp;

More rarely, hair loss in severe forms.

In the more severe forms, the lesions can spread to other areas of the skin, such as:

- The thorax (round and oval medallions between the two nipples);

- Armpits;

- Upper back;

- Eyelashes, which can lead to stye (infection of the pilosebaceous follicle of the eyelash, usually caused by Staphylococcus aureus), blepharitis (inflammation of the eyelids) or conjunctivitis;

- Skin folds, especially in overweight subjects.

Between outbreaks, the skin gradually regains its normal appearance, but remains fragile in the face of any aggression (friction, irritants). On another outbreak, the red patches come back, followed by dander and dandruff. In some people, only one area of ​​the skin is affected (often the scalp), while in others, several areas of the skin are affected simultaneously.

Seborrheic dermatitis is a benign disease, but it can have a significant impact on the quality of life, due to the visible symptoms of the disease (plaques, scales, dandruff on clothes, etc.).

Diagnosis of seborrheic dermatitis:

Clinical assessment

The diagnosis of seborrheic dermatitis is based on physical examination.

Seborrheic dermatitis of the scalp must be differentiated from other disorders:

Atopic Scalp Dermatitis: This disorder usually manifests first as a fine, white, dry scalp rather than the yellowish fatty flakiness of seborrheic dermatitis.

Scalp psoriasis: erythematous and scaly patches are clearly demarcated.

Rosacea: When rosacea affects the face, it first manifests as erythema, papules, and papulopustules but not peeling (however, patients can have both seborrheic dermatitis and rosacea).

Treatments of seborrheic dermatitis?

In mild forms of seborrheic dermatitis, which are limited to the scalp, patients can use a specific shampoo, based on active ingredients such as pyrithione zinc, piroctone olamine, selenium sulfide or salicylic acid. This type of shampoo is available without a prescription in pharmacies, but they are contraindicated:

- In pregnant women;

- For certain types of hair.

In the forms extended to the face and other areas of the body and / or when the shampoo has no effect, local medical treatment (shampoos, creams, foaming gels, etc.) becomes necessary. Several drugs can be used:

- Antifungals, first applied twice a week, then once a week and finally once every two weeks;

- Corticosteroids, the use of which must be occasional, given the risk of relapse on stopping and the side effects of these drugs (atrophy of the skin, depigmentation, rash;

- Lithium gluconate has anti-inflammatory action;

- Specific shampoos;

More rarely, calcineurin inhibitors, powerful immunosuppressants reserved for severe forms and long-term treatments.

Most often, these treatments must be repeated with each new outbreak, because they cannot permanently cure seborrheic dermatitis.

Treatments for seborrheic dermatitis must be accompanied by a few good habits on a daily basis, during and between outbreaks:

- Gentle hygiene of the skin and hair: remove antiseptic soaps, avoid perfumed, alcoholic, oily or potentially irritating cosmetics for the skin, favor a bar without soap or a mild cleanser;

- Wash the face twice a day, without rubbing, followed by the application of a moisturizing and soothing cream;

- Washing the hair with a mild shampoo, removing styling products and avoiding hair colorings;

- Reduction of triggering or aggravating factors: overweight, stress, excessive sweating, alcohol abuse, extreme temperatures;

- Systematic sun protection in the event of exposure to the sun.

Always consult a dermatologist if the symptoms of seborrheic dermatitis do not respond to frequent use of medicated shampoos.

Also see if the seborrheic dermatitis patches become infected, if fluid or pus appears, if a scab forms, or if it becomes very red and painful.