Learn more about contact dermatitis: introduction
Contact dermatitis is a type of eczema triggered by contact with a particular substance.
Eczema is the name for a group of conditions that cause skin to become dry and irritated.
Contact dermatitis usually improves or clears up completely if the substance causing the problem is identified and avoided. Treatments are also available to help ease the symptoms.
Symptoms of contact dermatitis
Contact dermatitis causes the skin to become itchy, blistered, dry and cracked.
Lighter skin can become red, and darker skin can become dark brown, purple or grey.
This reaction usually occurs within a few hours or days of exposure to an irritant or allergen.
Symptoms can affect any part of the body but most commonly the hands and face.
Learn more about contact dermatitis: symptoms
Contact dermatitis can cause skin to become inflamed (irritated), blistered, dry, thickened and cracked.
Lighter skin can become red, and darker skin can become dark brown, purple or grey.
These symptoms can develop on any area of the body, although the hands and face are most often affected.
Symptoms caused by an irritant usually appear within 48 hours, or even immediately. Milder irritants (such as soap and detergents) may not cause problems immediately – you may need frequent exposure to these before they cause problems.
Symptoms caused by an allergen, such as make-up or metal jewellery, often take several days to develop.
If you can avoid being re-exposed to the substance responsible for the reaction, your skin will usually clear up within a few days or weeks.
However, some people experience severe and long-lasting symptoms, which may affect their quality of life.
Depending on the substance that caused the reaction, you may also experience some additional symptoms.
For example, allergens may cause affected areas of the skin to itch and irritants may cause a burning or stinging sensation.
Occasionally, areas of skin affected by contact dermatitis can become infected. Signs of an infection can include:
- your existing symptoms getting rapidly worse
- discharge from your skin
- increasing pain
- feeling generally unwell
- feeling hot or shivery
Seek immediate medical advice if you think your skin may have become infected, as you may need to take antibiotics.
Learn more about contact dermatitis: causes
Contact dermatitis occurs when your skin reacts to a particular substance.
This can be either:
- an irritant – a substance that directly damages the outer layer of skin
- an allergen – a substance that causes your immune system to respond in a way that affects the skin
Irritant contact dermatitis
Irritant contact dermatitis may be caused by frequent exposure to a weak irritant, such as soap or detergent. It may also develop if you've been in contact with a stronger irritant for a short while.
You're at an increased risk of irritant contact dermatitis if you also have atopic eczema, which is the most common form of eczema.
Common irritants include:
- soaps and detergents
- antiseptics and antibacterials
- perfumes and preservatives in toiletries or cosmetics
- oils used in machines
- acids and alkalis
- powders, dust and soil
- water – especially hard, chalky water or heavily chlorinated water
- many plants – such as Ranunculus, spurge, Boraginaceae and mustards
If you already have irritant contact dermatitis symptoms, they can be made worse by heat, cold, friction (rubbing against the irritant) and low humidity (dry air).
Exposure at work
You may be more at risk of irritant contact dermatitis if you work with irritants as part of your job, or if your job involves a lot of wet work.
If you develop the condition because of a substance you work with, it may be referred to as occupational irritant dermatitis.
This type of dermatitis is more common in certain occupations, including:
- agricultural workers
- beauticians and hairdressers
- chemical workers
- construction workers
- cooks and caterers
- metal and electronics workers
- health and social care workers
- machine operators
- mechanics and vehicle assemblers
Allergic contact dermatitis
The first time you come into contact with an allergen, your body becomes sensitised to it, but does not react to it. It's only when you're exposed to the substance again that your immune system reacts and causes the skin to become red and itchy.
Allergens that commonly cause allergic contact dermatitis include:
- cosmetic ingredients – such as preservatives, fragrances, hair dye and nail varnish hardeners
- metals – such as nickel or cobalt in jewellery
- some topical medicines (medicines applied directly to the skin) – including topical corticosteroids, in rare cases
- rubber – including latex, a type of naturally occurring rubber
- textiles – particularly the dyes and resins that are contained in them
- strong glues – such as epoxy resin adhesives
- some plants – such as chrysanthemums, sunflowers, daffodils, tulips and primula
Learn more about contact dermatitis: diagnosis
A GP can usually diagnose contact dermatitis from the appearance of your skin and by asking about your symptoms.
They'll want to know when your symptoms first appeared and what substances you've been in contact with.
Identifying allergens and irritants
If a GP has diagnosed contact dermatitis, they'll try to identify what has triggered your symptoms. If the allergens or irritants can be identified, you can take steps to avoid those substances and reduce the risk of your symptoms flaring up.
A GP will look at your medical history and ask questions about your lifestyle and occupation. They may also ask whether there's a history of dermatitis or eczema in your family.
Referral to a specialist
If the allergens or irritants causing your contact dermatitis cannot be identified, you may be referred to a dermatologist (a doctor who specialises in treating skin conditions).
You may also be referred to a dermatologist if the trigger has been identified, but your symptoms are not responding to treatment.
Testing for allergens
The best way to test for a reaction to allergens is by patch testing. During a patch test, tiny amounts of known allergens are applied to your skin.
The substances are attached to your back using a kind of non-allergic tape. They may sometimes be attached to the upper arms.
After 2 days, the patches are removed and your skin assessed to check if there has been any reaction.
Your skin will usually be examined again after a further 2 days, as most allergic contact dermatitis reactions take this long to develop.
Testing for irritants
It's difficult to test whether specific products irritate your skin, because testing for these is unreliable.
In some cases, a repeated open application test (ROAT) is useful, particularly to assess cosmetics. A ROAT involves reapplying the substance onto the same area of skin twice a day for 7 days, to see how your skin reacts.
This is a particularly useful way for you to check your own cosmetics at home for reactions.
Learn more about contact dermatitis: treatment
If the substance causing your contact dermatitis can be identified and avoided, your symptoms should improve and may even clear up completely.
There are a number of treatments to help ease your symptoms if it's not possible for you to avoid the substance causing them.
A pharmacist will be able to recommend treatments like emollients (moisturisers), which you rub on your skin to stop it becoming dry.
Avoiding the cause
One of the most important steps in treating contact dermatitis is identifying and avoiding the allergens or irritants that affect you. If you can successfully avoid or reduce your exposure to the cause, you should not experience any symptoms.
It's not always easy to avoid irritants or allergens that affect you, but a pharmacist, GP or dermatologist (skin specialist) can suggest ways to minimise your contact with things that trigger your condition.
If you're exposed to irritants as part of your job, wear protective clothing to minimise any contact. Tell your employer about your condition, so they can help you avoid the causes as much as possible.
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 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 can be quite greasy, but they are the most effective at keeping moisture in the skin. Lotions contain the least amount of oil so are not greasy but can be less effective. Creams are somewhere in between.
Creams and lotions tend to be more suitable for inflamed (swollen) areas of skin. Ointments are more suitable for areas of dry skin that are not 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 pharmacist can recommend another product.
How to use emollients
Use your emollient frequently and in large amounts. Many people find it helpful to keep separate supplies of emollients at work or school.
To apply the emollient:
- use a large amount
- do not rub it in – smooth it into the skin in the same direction the hair grows
- for very dry skin, apply the emollient 2 to 4 times a day, or as prescribed by a doctor
- 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 that cause your contact dermatitis, make sure you apply emollients regularly during and after work.
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 pharmacist, who may be able to recommend an alternative product.
Be aware that some emollients contain paraffin and can be a fire hazard, so should not be used near a naked flame. Emollients added to bath water can make your bath very slippery, so take care getting in and out of the bath.
Contact dermatitis can cause lighter skin to become red, and darker skin to become dark brown, purple or grey.
If your skin is also sore and inflamed, a GP may prescribe a topical corticosteroid (a cream or ointment applied directly to your skin) that can quickly reduce the inflammation.
When used as instructed by a pharmacist or doctor, corticosteroids are a safe and effective treatment for contact dermatitis.
Choice of topical corticosteroid
Different strengths of topical corticosteroids can be prescribed, depending on the severity of your contact dermatitis and where the affected skin is.
You may be prescribed:
- a stronger cream for short-term use for severe contact dermatitis
- a weaker cream if the eczema is mild
- a weaker cream for use on your face, genitals or in the creases of your joints (such as your elbows), as your skin is thinner in these areas
- a stronger cream to use on your palms and the soles of your feet, as the skin is thicker here
How to use topical corticosteroids
When using corticosteroids, apply the treatment in a thin layer to all the affected areas. Unless instructed otherwise by your doctor, follow the directions on the patient information leaflet that comes with your medicine. This will give details of how much to apply.
During an episode of severe contact dermatitis, do not apply the corticosteroid more than twice a day. Most people only have to apply it once a day.
You should apply your emollient first and wait around 30 minutes before applying the topical corticosteroid.
The medicine will usually start to have an effect within a few days. Speak to a GP if you've been using a topical corticosteroid and your symptoms have not improved.
Topical corticosteroids may cause a mild, short-lived burning or stinging sensation as you apply them. In some 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 increases your risk of getting side effects. You should use the weakest and smallest amount possible to control your symptoms.
If you have a severe episode of contact dermatitis and it covers a large area of your skin, a doctor may prescribe corticosteroid tablets.
If steroid tablets are taken often or for a long time, they can cause a number of side effects, such as:
For this reason, a doctor is unlikely to prescribe repeat courses of corticosteroid tablets without referring you to a specialist.
If the treatments prescribed by a GP are not successfully controlling your symptoms, they may refer you for assessment and treatment by a dermatologist.
Further treatments that may be available from a dermatologist include:
- phototherapy – where the affected area of skin is exposed to ultraviolet (UV) light to help improve its appearance
- immunosuppressant therapy – medicines that reduce inflammation by suppressing your immune system
- alitretinoin – capsules licensed for severe eczema affecting the hands
Some people may choose to use complementary therapies for contact dermatitis, such as food supplements or herbal remedies, but there is often a lack of evidence to show they are effective in treating the condition.
If you are thinking about using a complementary therapy, speak to a GP first to make sure the therapy is safe for you to use. You should continue to use any other treatments prescribed by a GP.