Discoid eczema, also known as nummular or discoid dermatitis, is a long-term skin condition that causes skin to become itchy, reddened, swollen and cracked in circular or oval patches.
Without treatment, discoid eczema can last for weeks, months or even years. It may also keep recurring - often in the same area that was affected previously.
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Symptoms of discoid eczema
Discoid eczema causes distinctive circular or oval patches of eczema. They can affect any part of the body, although they don't usually affect the face or scalp.
The first sign of discoid eczema is usually a group of small red spots or bumps on the skin. These then quickly join up to form larger pink, red or brown patches that can range from a few millimetres to several centimetres in size.
Initially, these patches are often swollen, blistered (covered with small fluid-filled pockets) and ooze fluid. They also tend to be very itchy, particularly at night.
Over time, the patches may become dry, crusty, cracked and flaky. The centre of the patch also sometimes clears, leaving a ring of discoloured skin that can be mistaken for ringworm.
You may just have one patch of discoid eczema, but most people get several patches. The skin between the patches is often dry.
Patches of discoid eczema can sometimes become infected. Signs of an infection can include:
- the patches oozing a lot of fluid
- a yellow crust developing over the patches
- the skin around the patches becoming red, hot, swollen, and tender or painful
- feeling sick
- feeling unwell
When to seek medical advice
See your pharmacist or GP if you think you may have discoid eczema so they can recommend a suitable treatment.
You should also seek medical advice if you think your skin may be infected. You may need to use antibiotic cream or, in severe cases, take antibiotics.
Your GP should be able to make a diagnosis just by examining the affected areas of skin. In some cases they may also ask questions or arrange some tests to rule out other conditions.
Your GP may refer you to a dermatologist (a doctor who specialises in managing skin conditions) if they're unsure of the diagnosis or if you need patch testing.
Causes of discoid eczema
The cause of discoid eczema is unknown, although it may occur as a result of having particularly dry skin.
Dry skin means your skin can't provide an effective barrier against substances that come into contact with it. This could allow a previously harmless substance, such as soap, to irritate (damage) your skin.
It's important to look carefully at all the chemicals in cosmetics and toiletries that may have come into contact with your skin. Contact dermatitis, a type of eczema caused by coming into contact with a particular irritant, may have a role in discoid eczema.
Some people with discoid eczema also have a history of atopic eczema, which often occurs in people who are prone to asthma and hay fever. However, unlike atopic eczema, discoid eczema doesn't seem to run in families.
Other possible triggers
Some medicines may also be associated with discoid eczema, as patches of eczema can appear in people taking:
- interferon and ribavirin - when they're used together to treat hepatitis C
- tumour necrosis factor-alpha (TNF-alpha) blockers - used to treat some types of arthritis
- statins (cholesterol-lowering medication) - which can cause dry skin and rashes
Dry environments and cold climates can make discoid eczema worse, and sunny or humid (damp) environments may make your symptoms better.
Treating discoid eczema
Discoid eczema is usually a long-term problem, but medications are available to help relieve the symptoms and keep the condition under control.
Treatments used include:
- emollients - moisturisers applied to the skin to stop it becoming dry
- topical corticosteroids - ointments and creams applied to the skin that can help relieve severe symptoms
- antihistamines - medications that can reduce itching and help you sleep better
There are also things you can do yourself to help, such as avoiding all the irritating chemicals in soaps, detergents, bubble baths and shower gels.
Additional medication can be prescribed if your eczema is infected or particularly severe.
Occasionally, areas of skin affected by discoid eczema can be left permanently discoloured after the condition has cleared up.
Read about treating discoid eczema.
Other types of eczema
Eczema is the name for a group of skin conditions that cause dry, irritated skin. Other types of eczema include:
- atopic eczema (also called atopic dermatitis) - the most common type of eczema, it often runs in families and is linked to other conditions such as asthma and hay fever
- contact dermatitis - a type of eczema that occurs when the body comes into contact with a particular substance
- varicose eczema - a type of eczema that most often affects the lower legs and is caused by problems with the flow of blood through the leg veins
There's no simple cure for discoid eczema, but medications can help ease the symptoms.
- emollients - to use all the time
- soap substitutes - to replace irritating soaps and cleaning products
- topical corticosteroids - for flare-ups
- corticosteroid tablets - for severe flare-ups
- antibiotics - for infected eczema
- antihistamines - for severe itching
There are many different preparations for each type of medication and it's worth taking time with your pharmacist to find the best one for you.
A range of emollient products, soap substitutes and some topical corticosteroids can be bought from pharmacies without a prescription. Some of them are cheaper to buy this way than with a prescription.
Ask your pharmacist for advice on the different products and how to use them. See your GP if your eczema doesn't improve after using an over-the-counter preparation.
There are also some self-help tips that may help to control symptoms of discoid eczema, such as:
- avoiding soaps and detergents, including liquid soaps, bubble bath, shower gels and wet wipes - even if these don't obviously irritate your skin; use an emollient soap substitute instead
- protecting your skin from minor cuts (for example, by wearing gloves) as these may trigger discoid eczema
- taking daily lukewarm baths or showers - using an emollient when washing may reduce your symptoms, and remember to apply your treatments soon afterwards
- not scratching the skin patches - keeping your hands clean and your fingernails short may help reduce the risk of skin damage or infection from unintentional scratching
- making sure you use and apply your treatments as instructed by your GP or pharmacist
See your GP if you suspect your skin is infected. For example, if there's excessive weeping or tenderness in the patches of eczema.
Infection can spread quickly, and the use of topical corticosteroid creams can mask or further spread the infection.
Emollients are moisturising treatments applied directly to the skin to reduce water loss and cover it with a protective film. They're often used to help manage dry or scaly skin conditions such as eczema.
Choice of emollient
Several different emollients are available. You may need to try a few to find one that works for you. You may also be advised to use a mix of emollients, such as:
- an ointment for very dry skin
- a cream or lotion for less dry skin
- an emollient to use instead of soap
- an emollient to add to bath water or use in the shower
- one emollient to use on your face and hands, and a different one to use on your body
The difference between lotions, creams and ointments is the amount of oil they contain. Ointments contain the most oil so they can be quite greasy, but are the most effective at keeping moisture in the skin. Lotions contain the least amount of oil so aren't greasy, but can be less effective. Creams are somewhere in between.
Creams and lotions tend to be more suitable for red, inflamed (swollen) areas of skin. Ointments are more suitable for areas of dry skin that aren't inflamed.
If you've been using a particular emollient for some time, it may eventually become less effective or may start to irritate your skin. If this is the case, your GP will be able to prescribe another product.
How to use emollients
Use your emollient all the time, even if you're not experiencing symptoms, as it can help limit the return of your condition. Many people find it helpful to keep separate supplies of emollients at work or school.
To apply the emollient:
- use a large amount
- don't rub it in, smooth it into the skin in the same direction that the hair grows
- for very dry skin, apply the emollient every two to three hours
- after a bath or shower, gently dry the skin and then immediately apply the emollient while the skin is still moist
If you're exposed to irritants at work, make sure you apply emollients regularly during and after work.
Don't share emollients with other people.
Occasionally, some emollients can irritate the skin. If you have discoid eczema, your skin will be sensitive and can react to certain ingredients in over-the-counter emollients.
If your skin reacts to the emollient, stop using it and speak to your GP, who can recommend an alternative product.
Emollients added to bath water can make your bath very slippery, so take care getting in and out of the bath.
To treat the patches of discoid eczema, your GP may prescribe a topical corticosteroid (applied directly to your skin) to reduce the inflammation.
Choice of topical corticosteroid
There are different strengths of topical corticosteroids that can be prescribed depending on the severity of your eczema. Discoid eczema usually needs a stronger type of corticosteroid than other types of eczema.
You might be prescribed a cream to be used on visible areas, such as face and hands, and an ointment to be used at night or for more severe flare-ups.
How to use topical corticosteroids
When using corticosteroids, apply the treatment accurately to the affected areas. Unless instructed otherwise by your doctor, follow the patient information leaflet that comes with the corticosteroid.
Don't apply the corticosteroid more than twice a day. Most people only have to apply it once a day.
To apply the topical corticosteroid, take the following steps:
- apply your emollient first and ideally wait around 30 minutes before applying the topical corticosteroid, until the emollient has soaked into your skin
- apply a good amount of the topical corticosteroid to the affected area
- use the topical corticosteroid until the inflammation has cleared up, unless otherwise advised by your GP
Speak to your prescriber if you've been using a topical corticosteroid and your symptoms haven't improved.
Topical corticosteroids may cause a mild and short-lived burning or stinging sensation as you apply them. In rare cases, they may also cause:
- thinning of the skin
- changes in skin colour
- acne (spots)
- increased hair growth
Most of these side effects will improve once treatment stops.
Generally, using a stronger topical corticosteroid, or using a large amount of topical corticosteroid, will increase your risk of getting side effects. You should use the weakest and smallest amount possible to control your symptoms.
If you have a severe flare-up, your doctor may prescribe corticosteroid tablets to take for up to a week.
If corticosteroid tablets are taken often or for a long time, they can cause a number of side effects, such as:
- reduced growth rate in children
- high blood pressure (hypertension)
- osteoporosis (brittle bones)
For this reason, your doctor is unlikely to prescribe repeat courses of corticosteroid tablets without referring you to a specialist.
If your eczema becomes infected, you may also be prescribed an antibiotic.
If you have an extensive area of infected eczema, you may be prescribed an antibiotic to take by mouth. This is most commonly flucloxacillin, which is usually taken for one week.
If you're allergic to penicillin, you might be given an alternative such as clarithromycin.
If you have a small amount of infected eczema, you'll normally be prescribed a topical antibiotic, such as fusidic acid. This means the medicine is applied directly to the affected area of skin, in the form of an ointment or cream.
Some topical antibiotics are available in creams or ointments that also contain topical corticosteroids.
Topical antibiotics should normally be used for up to two weeks as necessary.
Antihistamines are a type of medicine that work by stopping the effects of a substance in the blood called histamine. Your body often releases histamine when it comes into contact with an irritant. Histamine can cause a wide range of symptoms, including sneezing, watery eyes and itching.
Antihistamines may be prescribed during flare-ups of discoid eczema to cope with the symptom of itching, particularly if it's interfering with your sleep. However, they won't treat the damaged skin.
Many older types of antihistamines can make you drowsy, which can be useful if your symptoms affect the quality of your sleep. Otherwise, ask your pharmacist or GP to recommend one of the more modern "non-sedating" antihistamines.
Some people may find complementary therapies, such as herbal remedies, helpful in treating eczema, but there's little evidence to show these remedies are effective.
If you're thinking about using a complementary therapy, speak to your GP first to ensure the therapy is safe for you to use. Make sure you continue to use other treatments your GP has prescribed.
If the treatments prescribed by your GP aren't successfully controlling your symptoms, they may refer you for assessment and treatment by a dermatologist (specialist in treating skin conditions).
Further treatments that may be available from your dermatologist include:
- phototherapy - where the affected area of skin is exposed to ultraviolet (UV) light to help reduce inflammation
- bandaging - where medicated dressings are applied to your skin
- immunosuppressant therapy - medicines that reduce inflammation by suppressing your immune system