What is discoid eczema?
Discoid eczema is a long-term skin condition that causes skin to become itchy, reddened, dry and cracked.
It's also known as nummular eczema.
It can affect any part of the body, but is usually seen on the:
- lower legs
- trunk (chest, tummy and back)
People with discoid eczema have circular or oval patches of eczema with well-defined edges. These can be a few millimetres to a few centimetres in size.
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The cause of discoid eczema is unknown, although it is often accompanied by dry skin and is thought to be triggered by irritation of the skin.
Discoid eczema tends to develop in adults and is rare in children. It is more common among men aged from 50 to 70 and women in their teens or twenties. When discoid eczema occurs in young women, they often have atopic eczema as well.
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Treating discoid eczema
See your doctor or pharmacist if you notice the symptoms of discoid eczema. If it is not treated it can last for months or even years. Even after treatment the condition may return, often with patches in the same places as before.
There are a number of different treatments available, such as(moisturisers applied to the skin to reduce the loss of water from the skin) and (creams containing steriod medication).
There are also things you can do yourself to help. For example, avoid irritating chemicals in some soaps and detergents, and using a moisturiser. Additional medication can be prescribed if your eczema is infected or particularly severe.
With the correct treatment, you can keep discoid eczema under good control.
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Discoid eczema symptoms
Discoid eczema causes distinctive circular or oval patches of eczema. They may be a few millimetres or several centimetres wide and are usually pink, red or brown.
Discoid eczema can be:
- dry – the patches are red, dry, cracked and scaly
- wet – the patches are bumpy and blistered (covered with small fluid-filled pockets) and ooze fluid. They may be very itchy and the fluid may dry and crust over.
Patches of discoid eczema may appear first as a dry patch, and then become wet and oozing as they develop.
Some people find the itching severe, and if it is bad at night this can affect your sleep. Other people may barely notice the itching. Discoid eczema may also cause a burning or stinging feeling.
You may just have one patch of discoid eczema, but most people have several patches. The skin between the patches will usually be normal, although it is often dry. The patches of discoid eczema can last for weeks or months if not treated.
Where the patches appear
Discoid eczema can appear anywhere on the body, but does not usually occur on the face or scalp. It most commonly occurs on the:
- lower legs
- trunk (the body, excluding the head, neck and limbs)
If you treat your discoid eczema and it then returns, the patches may be in the same place as before.
Discoid eczema causes
The cause of discoid eczema is unknown, although it is often accompanied by dry skin.
One theory is that having dry skin means your skin cannot provide an effective barrier against substances that come into contact with it. A previously harmless substance, such as soap, can then irritate (damage) your skin., a type of eczema caused by coming into contact with a particular irritant, may therefore have a role in causing discoid eczema.
Discoid eczema may also be linked to, which often occurs in people who are prone to eczema, and . However, unlike atopic eczema, discoid eczema does not seem to run in families.
Other possible causes
An outbreak of discoid eczema may be triggered by a minor skin injury, such as anor a .
Some medicines may also be associated with discoid eczema, as patches of eczema can appear in people taking:
- interferon and ribavirin – when they are used together to treat
- tumour necrosis factor (TNF) blockers – which are used to treat some types of
Dry environments or cold climates will make discoid eczema worse and sunny or humid (damp) environments may make your symptoms better.
Diagnosing discoid eczema
As discoid eczema causes distinctive symptoms, your doctor should be able to make a diagnosis by examining the affected areas of skin.
In some cases your doctor may also ask questions or carry out some tests to rule out other conditions. Possible tests include:
- swab test to check for infection – a swab is wiped over your skin and tested for bacteria that may cause an infection
- examining the flakes of skin to check for fungal skin infection, such as , which also causes a ring-like red rash
- patch testing may be used in rare cases to rule out – small amounts of different substances are applied to your skin to see if they cause a reaction
Patch tests are usually negative in people with discoid eczema.
Your doctor may refer you to a dermatologist (a doctor who specialises in treating skin conditions) if they are unsure of the diagnosis or if you need patch testing.
Treating discoid eczema
There is no simple cure for discoid eczema. However, there are treatments that can ease symptoms during an eczema flare-up.
Medication used to treat discoid eczema includes:
- (to use all the time)
- (for flare-ups)
- (for severe flare-ups)
- (for infected eczema)
- (for severe itching)
There are many different preparations for each type of treatment. It is often a matter of practicality and personal preference to find the best preparation for you, and this may take time.
There are also some self-help tips which may help to control symptoms of discoid eczema. This includes:
- avoiding soaps and detergents, including liquid soaps, bubble bath, shower gels and wet wipes - even if these do not obviously irritate your skin you should use an emollient instead of soap
- protecting your skin from minor cuts (for example, by wearing gloves) as they often trigger discoid eczema
- taking daily lukewarm baths or showers - using an emollient when washing may reduce your itching and remember to apply your treatments after your bath or shower
- keeping your fingernails short to reduce skin damage from scratching
- making sure you use and apply your treatments as instructed by your doctor or pharmacist - treatment failure is often due to people not using enough of the prescibed medication
A range of emollient products and some topical corticosteroid preparations 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. If your eczema does not improve after one week of using an over-the-counter preparation, see your doctor.
Emollients are substances that help soften and smooth your skin to keep it supple and moist. They are one of the most important forms of treatment for all types of eczema.
As discoid eczema can cause your skin to become dry and cracked, it is important to keep it moisturised to prevent it from becoming further irritated. Emollients prevent water being lost from the outer layer of the skin, and add water to the skin. They act as a protective barrier to keep the moisture in and the irritants out.
Choice of emollient
There are a variety of emollients available. Your doctor will be able to recommend a suitable product if you have discoid eczema.
You may need to try a few different emollients to find one that works for you. You may also be prescribed a mix of emollients, for example:
- an ointment for very dry skin
- a cream or lotion for less dry skin
- an emollient to use on your face and hands
- a different emollient to use on your body
- an emollient to use instead of soap
- an emollient to add to bath water or use in the shower
The difference between lotions, creams and ointments is the amount of oil they contain. Ointments contain the most oil so can be quite greasy, but are the most effective at keeping moisture in the skin. Lotions contain the least oil so are not greasy but can be less effective. Creams are in the middle.
Some people find emollients can irritate their skin. If this happens, speak to your pharmacist or doctor so an alternative emollient can be prescribed instead.
How to use emollients
Use your emollient all the time, even if you are not experiencing symptoms. Many people find it helpful to keep separate supplies of emollients at work or school.
To apply the emollient:
- use a large amount
- smooth the emollient into the skin in the same direction that the hair grows
- do not rub the emollient in
- for very dry skin, apply emollient every three to four hours
- after a bath or shower, gently dry the skin and then immediately apply emollient, while the skin is still moist
- do not share emollients with other people
Occasionally some emollients can irritate the skin. If you have contact dermatitis, your skin will be sensitive and can sometimes react to certain ingredients such as perfume in over-the-counter emollients. If your skin reacts to the emollient, stop using it and speak to your doctor, who will be able to recommend an alternative product.
If you are using an emollient for the first time, you may want to apply a small amount for a day or two before applying it to a widespread area. This will allow you to check whether your skin reacts to it or not.
Some emollients contain paraffin and can be a fire hazard. As some emollient products are highly flammable, they should not be used near a naked flame.
Emollients that are added to your bath can make your bath very slippery, so take care getting in and out. As long as you are aware of these hazards, you should be able to use emollients safely.
If you have patches of discoid eczema, your doctor may prescribe a topical corticosteroid (one that is applied directly to your skin). Corticosteroids work by quickly reducing inflammation.
Corticosteroids are any type of medication that contains steroids, a type of hormone. Hormones are groups of powerful chemicals that have a wide range of effects on the body.
You may be concerned about using medication that contains steroids. However, corticosteroids are not the same as, which are sometimes used (illegally) by bodybuilders and athletes. When used as instructed by your pharmacist or doctor, corticosteroids are one of the safest and most effective treatments for discoid dermatitis.
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
- an ointment to be used at night or for more severe flare-ups
If you need to use corticosteroids frequently, visit your doctor regularly so they can check the treatment is working.
How to use topical corticosteroids
When using corticosteroids, apply the treatment accurately to the affected areas. Unless instructed otherwise by your dermatologist, you should follow directions on the patient information leaflet that comes with the corticosteroid. Do not apply the corticosteroid more than twice a day. Most people will only have to apply it once a day.
To apply the topical corticosteroid, take the following steps:
- apply your emollient first and wait several 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 doctor
Speak to your prescriber if you have been using a topical corticosteroid and your symptoms have not improved after three to four weeks.
Topical corticosteroids may cause a mild burning or stinging feeling at first. If used for long periods of time they may also cause:
- thinning of the skin – particularly in the crease of the elbow or knee joint
- telangiectasia (visible blood vessels) – particularly on the cheeks
- increased hair growth
These side effects are rare.
Generally, using a stronger or larger amount of topical corticosteroid may increase your risk of side effects. For this reason, use the weakest and smallest amount possible to control your symptoms.
If you have a severe flare-up, your dermatologist may prescribe oral corticosteroids. These contain steroids, as topical corticosteroids do, but are tablets that you swallow.
If oral corticosteroids are taken often or for a long time they can also cause side effects, such as:
- affecting the growth rate of children
- (brittle bones)
For this reason, your doctor is unlikely to prescribe repeat courses of oral corticosteroids without referring you to a specialist.
If your eczema appears to be infected, you may also be prescribed an antibiotic.
If you have an extensive area of infected eczema, your doctor may prescribe an antibiotic to take by mouth. The antibiotic most commonly prescribed is flucloxacillin, usually taken for one week. If you are allergic to penicillin, you might be given an alternative such as clarithomycin instead.
If you have a small amount of infected eczema, you will 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.
Topical antibiotics should normally be used for 7-10 days as necessary.
You can help prevent your eczema becoming infected by keeping your hands clean and your nails short. Try not to scratch as this can make infection more likely.
If you suspect your eczema is infected, for example because there is excessive weeping or soreness in the patches of eczema, see your doctor. Infection can spread quickly, and the use of corticosteroid creams can mask or further spread the infection.
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 allergen. 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 is interfering with your sleep. However, they will not treat the damaged skin.
Many older types of antihistamines can make you drowsy. Ask your pharmacist or doctor to recommend one of the more modern “non-sedating” antihistamines. These are safer and less likely to make you drowsy.
In some severe cases of discoid eczema, your doctor may refer you for assessment and treatment by a dermatologist (a skin specialist).
Some treatments a dermatologist may offer are explained below. These types of treatments are not suitable for everyone, and can only be carried out by experienced skin-care specialists.
Possible treatments include:
- phototherapy – where your eczema is exposed to ultraviolet (UV) light
- bandaging – where medicated dressings are applied to your skin
- immunosuppressant medication – a medicine that suppresses your immune system (the body’s natural defence system)