Yellowish, greasy scales at the roots of the hair, reddened skin underneath, and itching that worsens during periods of stress or in cold weather. The same pattern often appears on the eyebrows, at the sides of the nose and behind the ears. This is seborrheic dermatitis: a close relative of dandruff, but not the same thing.
In summary
- Seborrheic dermatitis is a chronic inflammation of areas rich in sebaceous glands: the scalp, face, behind the ears and sometimes the chest.
- Compared with dandruff, there is redness, the scales are thicker and the itching is more intense.
- It occurs in phases: it improves and returns, often in autumn and winter or during periods of stress. It is not contagious and is not caused by poor hygiene.
- Diagnosis and any treatments should be provided by a doctor. Cosmetics help maintain the result and reduce recurrences.
Article written by Elisa Avalle, founder of LeLang Skin Care and dermocosmetics specialist. Cover image generated with the support of artificial intelligence.
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What is seborrheic dermatitis
It is a very common inflammatory skin condition that appears where sebaceous glands are most numerous. On the scalp, it is the most common form. Research describes it as one end of the same spectrum whose other end is dandruff: the same key factors, but different intensity.
There are three key factors: Malassezia, a yeast that normally lives on everyone's skin; sebum, which it feeds on; and the skin's response, which in some people reacts with inflammation to the products of sebum breakdown. The mechanism is described in the guide to dry or greasy dandruff.
How to recognise it
- Scales that are yellowish, greasy and thicker than dandruff, adhering to the skin and hair.
- Redness beneath the scales, sometimes visible along the hairline.
- Itching, of varying intensity.
- Other areas often affected: eyebrows, creases at the sides of the nose, behind the ears, beard. On the face, we discuss it in our in-depth article on facial seborrheic dermatitis.
Dandruff, seborrheic dermatitis or psoriasis?
| Dandruff | Seborrheic dermatitis | Scalp psoriasis | |
|---|---|---|---|
| Redness | Absent | Present, faded | Net-like, patchy |
| Flakes | Small, white, or yellowish | Yellowish, greasy | Thick, silvery, dry |
| Edges | No defined patch | Faded | Clearly defined, often extending beyond the hairline |
| Other areas | No | Eyebrows, sides of the nose, ears | Elbows, knees, nails |
The table is intended as a guide and does not replace a diagnosis. Conditions may overlap, and a doctor or dermatologist can distinguish between them.
Why it comes back
Seborrheic dermatitis follows a relapsing course. Factors that can trigger a flare-up include:
- cold weather and dry air: for many people, it worsens between autumn and winter and improves in summer;
- stress and too little sleep;
- washing too infrequently, allowing sebum and flakes to build up;
- greasy styling products applied to the roots.
It is more common in men, young adults, and people with certain neurological conditions, such as Parkinson's disease. In newborns, there is a distinct form, cradle cap, which should always be assessed by a pediatrician.
The doctor's role
You need to see a doctor or dermatologist:
- for the initial diagnosis, especially if the redness is pronounced or affects the face;
- if the itching disrupts sleep or there are crusts, pain, or oozing;
- if the appropriate shampoo, used correctly for four to six weeks, does not produce results;
- if bald patches or plaques with clearly defined edges appear.
For acute flare-ups, treatments are available, including medicated shampoos, which must be prescribed by a doctor. They should not be used without medical advice or stopped suddenly.
What cosmetics can do
Between flare-ups, and alongside treatment when there is one, cosmetic products help keep flakes, sebum, and itching under control. What is needed:
A shampoo with the right active ingredients
- actives targeting Malassezia, such as piroctone olamine and climbazole;
- keratolytic ingredients, such as salicylic acid, to remove flakes;
- sebum-regulating ingredients, such as zinc PCA;
- soothing ingredients, such as bisabolol.
How to use it
- Apply it to the scalp and leave it on for two to three minutes, massaging with your fingertips.
- During active phases, use it every time you wash your hair; when the situation is calm, alternate it with a gentle shampoo, without stopping it abruptly.
- If the flakes are thick, soften them before washing with a specific keratolytic product, without scratching them off.
- Use lukewarm water, keep the hairdryer at a distance, and do not tie your hair up while it is still wet.
Consistency, not intensity, is the key. Seborrheic dermatitis cannot be “eliminated” with a course of shampoo: it is kept under control with regular maintenance, intensified at the first signs of a relapse.
Frequently asked questions
Does seborrheic dermatitis go away?
It is a chronic condition: it may remain quiet for months and then flare up again. With treatments recommended by your doctor and good cosmetic maintenance, it can be kept under control.
Does it cause hair loss?
Generally, no. Intense, prolonged inflammation can increase hair shedding, which usually returns to normal when the skin calms down. If thinning patches appear, see a dermatologist.
Can you wash your hair every day?
Yes, when needed. Washing too infrequently allows sebum and flakes to build up. The important thing is to choose a suitable, non-irritating shampoo.
Is a special diet needed?
There is no strong evidence that a specific diet can cure it. A balanced diet and good sleep support overall skin health.
The next step
If seborrheic dermatitis also affects the face, your skincare routine is just as important as your shampoo. The pharmacist at LeLang partner pharmacies and para-pharmacies can help you choose products for your scalp and understand when it is time to see a doctor.
Does the dermatitis also affect the face?
Book a free virtual consultation: together, we will assess the routine best suited to your skin.
Sources for this article
- Borda L.J., Wikramanayake T.C. (2015). "Seborrheic dermatitis and dandruff: a comprehensive review". Journal of Clinical and Investigative Dermatology, vol. 3, no. 2.
- Clark G.W., Pope S.M., Jaboori K.A. (2015). "Diagnosis and treatment of seborrheic dermatitis". American Family Physician, vol. 91, no. 3, pp. 185-190.
- Dall'Oglio F. et al. (2022). "An overview of the diagnosis and management of seborrheic dermatitis". Clinical, Cosmetic and Investigational Dermatology, vol. 15, pp. 1537-1548.
Where to continue: Dry or oily dandruff · Seborrheic dermatitis of the face · Piroctone olamine and climbazole
