Seborrheic Dermatitis of the Scalp: How to Treat it?

Seborrheic dermatitis is a chronic inflammatory skin condition affecting approximately 2% of the population. It typically presents in sebum-rich areas, that is, zones containing a high concentration of sebaceous glands. This is why symptoms appear on the scalp, but also other parts of the face: the bridge of the nose, eyebrow, cheeks, etc.

Seborrheic dermatitis on the scalp is the most common form of this condition. It is also referred to as Pityriasis simplex. It is characterised by the presence of redness and scales on the scalp. When it is not inflammatory, the scalp is covered with scales that can be easily detached, particularly during showering or styling. However, when this form of seborrheic dermatitis is inflammatory, the scales are thicker and stick to the scalp.

The symptoms of seborrheic dermatitis appear in flare-ups. During these episodes, the itching can be intense. Some individuals may also experience irritation and occasionally burning sensations. These are common in cases of seborrheic dermatitis of the scalp. This skin condition is not contagious, but the quality of life can be negatively impacted when symptoms arise.

The causes of seborrheic dermatitis are not clearly defined. However, certain factors have been identified, including an excessive proliferation of a yeast called Malassezia. This yeast feeds on sebum and has the ability to convert it into fatty acids. These fatty acids produce prostaglandins that modulate the inflammatory response. When an excessive amount of these fatty acids is produced, the immune system may perceive this as a threat and react by triggering an inflammatory response that can result in redness, itching, and irritation of the scalp. Thus, a sebum-rich environment like the scalp promotes the excessive proliferation of this yeast, leading to the onset of seborrheic dermatitis.

Seborrheic dermatitis could be associated with hormones, as it tends to develop during puberty and is more common in men than in women, suggesting a possible influence of androgens on the pilosebaceous unit. However, further studies are needed to delve deeper into this relationship.

Other factors have been mentioned, such as immunological and environmental factors, underlying diseases, or lifestyle, which could increase the predisposition to seborrheic dermatitis. However, it remains challenging to precisely explain the link between these factors and the onset of this disease, thus necessitating further studies to delve deeper into this subject.

There are several treatments available to slow the progression of seborrheic dermatitis on the scalp. Here is a non-exhaustive list of solutions:

We find shampoos containing selenium sulphide (from 1 to 2.5%). This is an antifungal active ingredient that will limit the proliferation of the yeast Malassezia. However, its mechanism of action is still unknown. This treatment should initially be applied daily, leaving it on for 5 to 10 minutes, then subsequently twice a week. It has been deemed safe, non-toxic and effective.

Shampoos containingsalicylic acid can be effective in treating seborrheic dermatitis of the scalp. Salicylic acid has the ability to penetrate the upper layers of the skin, the epidermis, due to its liposoluble chemical structure. Once absorbed, it works by dissolving the adhesive bonds between dead skin cells, thus promoting their detachment and removal. Thanks to its keratolytic activity, it can help to remove dead skin cells, thus promoting cell renewal and the healing process of the scalp. Salicylic acid also plays a role in the cascade of inflammatory reactions and inhibits the synthesis of prostaglandins E2, molecules responsible for inflammatory and painful effects. It thus helps to soothe the scalp from itching and irritation caused by seborrheic dermatitis. These shampoos should be used twice a week.

This type of topical treatment allows for direct action at the scalp level by limiting inflammation and combating the proliferation of yeast Malassezia.

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