What causes eczema on the face and scalp?

Why does atopic eczema develop?

Atopic eczema involves genetic susceptibility, environmental triggers and changes in immune system activity. These can weaken the skin barrier, the protective outer layer, making skin more vulnerable to irritants and infection. It often runs in families and is associated with asthma and hay fever, although the exact cause is not always known.45

A weakened barrier lets water escape and irritants and bacteria enter. Soaps, shampoos, hard water and central heating can increase dryness and worsen eczema. Atopic eczema can affect any area, and facial patches are particularly common in babies and toddlers.156

Other flare triggers include heat, temperature changes, stress, infections, detergents, pollen, pets and house dust mites. Hormonal changes during pregnancy can also worsen atopic eczema. A trigger worsens an existing tendency; it is not necessarily the original cause.5

Why are the scalp, eyebrows and sides of the nose affected?

Seborrheic dermatitis causes a scaly rash in oily areas, especially the scalp, eyebrows, ears, beard and skin around the nostrils. Scale can be white to yellowish, dry or greasy, and itchy. On darker skin, patches can look pink, purple or lighter than surrounding skin; on lighter skin, they tend to look red and raised.3

Dandruff is considered its mildest form, but seborrheic dermatitis also causes inflammation and can extend beyond the scalp. Stress and winter or early spring often bring flares. In adults, symptoms can come and go for years. Neither seborrheic dermatitis nor atopic eczema is contagious.35

Could skincare or hair products be responsible?

Contact dermatitis develops when something touching skin irritates it or causes an allergic reaction. Soap and hair dye can irritate skin; fragrance can cause an allergic reaction. Even a product used for years can become responsible. The rash tends to clear once exposure stops, but identifying the culprit can require a dermatologist's help.2

What should you do next?

For dry eczema, moisturising helps skin feel better. A moisturiser can also serve as a soap substitute, which gives one bathroom bottle two jobs for once.7

• Avoid known triggers and scented products. Do not remove food groups unless a doctor advises it; dietary restriction does not cure eczema.
• Apply an emollient, meaning a moisturising treatment, at least twice daily and after bathing. Continue when the skin improves.
• If using prescribed steroids, follow the instructions for the location, frequency and duration. The face needs particular care because it is prone to side effects.

Creams, gels and ointments are different moisturiser formats, not three compulsory additions to the bathroom inventory. A cream can be practical during the day and an ointment at night. If using an emollient and a steroid, leave 30 minutes between applications.6

Seborrheic dermatitis usually needs treatment to clear, sometimes including dandruff shampoo and a short course of medicine applied to skin. Get the diagnosis checked rather than treating every facial or scalp rash as dry eczema.2

When should you see a doctor?

See a doctor if treatment is not helping, or a dermatologist if facial redness lasts more than two weeks. Seek urgent medical help for blistering, leaking fluid, pus, pain, swelling, warmth, sudden worsening, fever or feeling unwell. These can indicate infection or a more serious complication.25