What are the aims of this leaflet?
This leaflet has been written to help you understand more about seborrhoeic dermatitis (also known as seborrhoeic eczema). It tells you what it is, what causes it, what can be done about it, and where you can find out more about it.
What is seborrhoeic dermatitis?
‘Dermatitis’ is a red, itchy, flaky (inflamed) skin complaint; ‘seborrhoeic’ means that the rash affects greasy (sebaceous) skin zones such as the face, scalp and centre of the chest.
Seborrhoeic dermatitis is very common and many people don’t even know they have it. Overall it has been reported to affect about 4% of the population, and dandruff (which is mild seborrhoeic dermatitis of the scalp) can affect almost half of all adults. It can start at any time after puberty and is slightly commoner in men. Babies can also get a short lived type of seborrhoeic dermatitis in the scalp (cradle cap) and nappy area, which usually clears after a few months.
What causes it?
It is thought that seborrhoeic dermatitis is triggered by an overgrowth of a harmless yeast called Malassezia that lives on the skin, or an over-reaction by the skin’s immune system to this yeast. These are not the same as the yeasts that cause thrush or those that are present in foods.
Seborrhoeic dermatitis is not usually linked to any underlying illness, but it can be stubborn and severe in people with HIV infection and it is also common in people with Parkinson’s disease.
Tiredness and stress can sometimes trigger a flare of seborrhoeic dermatitis. It is more common in cold than in warm weather, and it is not related to diet.
How is it treated?
Seborrhoeic dermatitis is managed with treatment that reduces the level of skin yeast – these include creams and shampoo, which can be used safely on a long-term basis.
Mild steroid creams can be used for short periods to settle any irritation, and the newer non-steroid anti-inflammatory eczema creams (calcineurin inhibitors) are also effective though not licensed for this complaint.
Is it hereditary?
What are the symptoms of seborrhoeic dermatitis?
The symptoms of seborrhoeic dermatitis seem to vary from person to person. Affected areas can be itchy, sore and sensitive and flaking skin can be bothersome and embarrassing, especially with dark clothing. Some people have the rash without being troubled.
What does it look like?
Affected areas are red with greasy looking skin flakes. It usually affects one or two body areas but can sometimes be widespread. The commonest sites are:
On the scalp:seborrhoeic dermatitis here ranges from mild flaky skin (dandruff) to a redder, scalier and sometimes weeping rash.
On the face:it often affects the inner eyebrows and creases around the nose and cheeks. The eyelids may also become red, swollen and flaky (seborrhoeic blepharitis).
In and around the ears:some people have inflammation inside the ear canals, in the cup of the ear and behind the ears. The skin can get infected with bacteria which result in oozing and crusting. Inflammation in the ear canal (otitis externa) can cause it to become blocked.
On the front of the chest and between the shoulder blades: it shows up as well-defined, round pink-red patches with mild scaling.
In the skin folds:it often affects moist areas such as the skin under the breasts, in the groin, under the arms, or in folds of skin on the abdomen. The skin is pink and shiny with surface cracks.
In darker skin:affected areas may look lighter (hypopigmented) or darker (hyperpigmented) than surrounding skin.
How is it diagnosed?
The diagnosis is made by examining the rash. It is not usually necessary to take a skin sample (biopsy) or to do any blood tests. If seborrheic dermatitis is severe or unresponsive to treatment and someone is at risk of HIV they may get tested. This is important as early treatment of HIV reduces the risk of passing it on and improves the health of the affected person.
If there is a suspicion of ringworm of the scalp, then skin scrapings can be sent to look for tinea fungus (mycology).
Seborrhoeic dermatitis can be difficult to distinguish from other kinds of dermatitis when certain areas such as the eyelid or genital area are affected or if it is very widespread. Severe scalp seborrhoeic dermatitis can resemble psoriasis. In psoriasis, the scales are thicker and whiter and the face is not usually affected.
Can it be cured?
Treatment can improve and sometimes clear seborrhoeic dermatitis, but there is no permanent cure and the complaint tends to come back when treatment is stopped.
How is treatment used?
Treatment is usually needed on a long-term basis, though sometimes it is possible to take a break. The choice depends on which areas of the body are affected and whether there is a lot of irritation:
In the scalp: medicated, anti-dandruff shampoos containing agents such as zinc pyrithione, selenium sulphide or ketoconazole can be used regularly. For best results, wash into the scalp, then wait 5-10 minutes before rinsing. Thick scales can be removed before shampooing by applying a descaling preparation containing coconut oil and salicylic acid for several hours or overnight. This can be messy, but it usually works well. If irritation is troublesome, your doctor may prescribe a steroid scalp lotion, gel or shampoo for occasional use.
Elsewhere:anti-yeast creams or ointments are usually effective and can be used safely as long-term treatment. Examples include clotrimazole, miconazole and nystatin. They are sometimes combined with a mild steroid for a few weeks to settle inflammation.
Washing your body with an antifungal shampoo containing ketoconazole may also help. Leave the shampoo on for '5 minutes or so before rinsing it off.
In the ear canals: medicated eardrops may help. Do not clean the ears with cotton buds as this causes more irritation.
On the eyelids: carefully cleaning between the lashes with an eyelid cleanser or baby (non-sting) shampoo helps to lift skin flakes and reduce inflammation.
Occasionally, if the rash is widespread or resistant to the treatments listed above, your doctor may suggest a short course of an oral anti-yeast medication.
What can I do?
Once your scalp is clear, continue using an anti-fungal shampoo once a week to reduce the chance of the rash coming back. A plain moisturiser may help to reduce scaling and redness of the skin. Changing your diet is not likely to make any difference.
Where can I get more information about it?
Web links to detailed leaflets:
For details of source materials used please contact the Clinical Standards Unit (firstname.lastname@example.org).
This leaflet aims to provide accurate information about the subject and is a consensus of the views held by representatives of the British Association of Dermatologists: individual patient circumstances may differ, which might alter both the advice and course of therapy given to you by your doctor.
This leaflet has been assessed for readability by the British Association of Dermatologists’ Patient Information Lay Review Panel
BRITISH ASSOCIATION OF DERMATOLOGISTS
PATIENT INFORMATION LEAFLET
PRODUCED AUGUST 2004
UPDATED JANUARY 2012, FEBRUARY 2015, APRIL 2018
REVIEW DATE APRIL 2021