Seborrheic dermatitis of the scalp: causes and treatments

Seborrheic dermatitis of the scalp is the most common form of dermatitis.
The scalp is affected in over 80%⁽¹⁾ of cases of seborrheic dermatitis.
What’s the best way to recognise it and not confuse it with other scalp conditions such as psoriasis or eczema? Is there a link between seborrheic dermatitis of the scalp and hair loss? In this article, we’ll take a look at the most important answers to this question.

Symptoms and diagnosis of seborrheic dermatitis of the scalp

Depending on the severity of the condition, the following may be observed: 

• simple dandruff in the mildest forms.
• greasy, yellowish dandruff related to excess sebum (hyper-seborrhoea) and reddening of the skin (erythema).

Lesions can appear all over the scalp, but are most often found at the top of the head (vertex), on the temples (parietal areas), and at the edge of the scalp, forming what is known as the "seborrheic crown".

Although the redness (erythema) on the scalp is often masked by hair, dandruff can be clearly visible, which gives the condition its characteristic appearance. Itching, known as pruritus, is also common and can be very intense, having a major impact on quality of life on a daily basis ⁽¹⁾.

Seborrheic dermatitis of the scalp can also sometimes be combined with hair loss, especially in men suffering from androgenetic alopecia. This combination may manifest itself through itching, without the appearance of dandruff or red patches.

Differentiation from other scalp conditions

Seborrheic dermatitis of the scalp is sometimes difficult to recognise because some symptoms can be confused with those of other conditions, such as psoriasis, eczema or ringworm.
It is therefore important to seek the advice of a healthcare professional first to ensure a reliable diagnosis and appropriate treatment.

The clinical examination will clearly identify the following symptoms ^{(2) (3)}:

Seborrheic dermatitis of the scalp and simple dandruff?

The notion of “dandruff” is still poorly defined. This term can refer to a number of situations, including a mild form of seborrheic dermatitis of the scalp, or the consequence of using unsuitable shampoos or cosmetics. In these cases, the condition is known as pityriasis capitis simplex, or simple dandruff. 

The relationship between seborrheic dermatitis of the scalp and simple dandruff is also often debated. In scientific literature, the term “dandruff” is sometimes used to refer to various flaky scalp conditions, regardless of their origin.

Prevention: lifestyle and preventive measures

To prevent seborrheic dermatitis of the scalp as much as possible, it’s important to take a general approach and adopt the following dietary and hygiene habits: 

In terms of your skincare routine:

• Follow a regular, personalised hair care routine using products specifically formulated for seborrheic dermatitis of the scalp.
• Avoid aggressive products that can irritate the scalp, such as hair dyes and styling products.
• Rinse your scalp thoroughly after each wash. 
• Use a soft bristle brush for styling and avoid removing flakes with your fingernails. 
• Use gentle shampoos between flare-ups to maintain a healthy scalp.

In terms of lifestyle:

• Avoid triggers such as exhaustion or fatigue. 
• Practise stress-management techniques such as meditation, yoga or deep breathing. 
• Maintain a healthy weight by adopting an active, balanced lifestyle.
• Limit alcohol and tobacco consumption as much as possible. 
• Eat a healthy, balanced diet that’s rich in vegetables, fibre and essential fatty acids, and avoid ultra-processed foods, which are often linked to skin inflammation. 

How is seborrheic dermatitis of the scalp treated?

Seborrheic dermatitis is a chronic condition which progresses in flare-ups, alternating between recurrences and remissions. There is no cure for seborrheic dermatitis, but there are highly effective treatments, both medicinal and cosmetic.
The treatments used for seborrheic dermatitis of the scalp are designed to relieve symptoms and minimise recurrence. This is why they act on several levels: 

• On hyper-seborrhoea by absorbing excess surface sebum. 
• Against the proliferation of Malassezia yeasts, thanks to an antimycotic or antifungal action. 
• On dandruff thank to a deflaking action. 
• Against redness and itching thanks to an anti-inflammatory action.