The terms eczema and dermatitis mean much the same. That is, an inflammation of the skin. It causes red, itchy skin which may also blister. There are two main types of dermatitis/eczema:
- Atopic eczema. This is caused by a problem from within the body. If you have atopic eczema you are born with a tendency for your skin to become inflamed. Various parts of the skin tend to flare up with inflammation from time to time, usually on both sides of your body.
- Contact dermatitis. This is caused by a substance from outside the body. This typically causes patches of inflammation on areas of skin which have come into contact with the substance. If you avoid the offending substance, the skin inflammation should go away.
What are topical steroids and how do they work?
Topical steroids are creams, ointments and lotions which contain steroid medicines. Topical steroids work by reducing inflammation in the skin. They are used for various skin conditions, including eczema. (Steroid medicines that reduce inflammation are sometimes called corticosteroids. They are very different to the anabolic steroids which are used by some bodybuilders and athletes.)
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What types of topical steroids are there?
There are many types and brands of topical steroid. However, they are generally grouped into four categories depending on their strength - mild, moderately potent, potent and very potent. (Potent just means 'strong', but doctors tend to use the word potent.) There are various brands and types in each category. For example, hydrocortisone cream 1% is a commonly used steroid cream and is classed as a mild topical steroid. The greater the strength (potency), the more effect it has on reducing inflammation but the greater the risk of side-effects with continued use.
Creams (which are usually white) are usually best to treat moist or weeping areas of skin. Ointments (which are clear, rather than white) are usually best to treat areas of skin which are dry or thickened. Lotions (which are like thin creams) may be useful to treat hairy areas such as the scalp.
When and how are topical steroids used?
As a rule, a course of topical steroid is used when one or more patches of eczema flare up. The aim of treatment is to clear the flare-up and then to stop the steroid treatment.
It is common practice to use the lowest-strength topical steroid which clears the flare-up. So, for example, hydrocortisone 1% is often used, especially when treating children. This often works well. If there is no improvement after 3-7 days, a stronger topical steroid is usually then prescribed. For severe flare- ups a very strong topical steroid may be prescribed from the outset.
Sometimes two or more preparations of different strengths are used at the same time. For example, a mild steroid for the face and a moderately strong steroid for eczema on the thicker skin of the arms or legs. A very strong topical steroid is often needed for eczema on the palms and soles of the feet of adults because these areas have thick skin.
You should use topical steroids until the flare-up has completely gone and then stop using them. In many cases, a course of treatment for 7-14 days is enough to clear a flare-up of eczema. In some cases, a longer course is needed.
Many people with eczema require a course of topical steroids every now and then to clear a flare-up. The frequency of flare-ups and the number of times a course of topical steroids is needed vary greatly from person to person. After you finish a course of topical steroid, continue to use moisturisers (emollients) every day to help prevent a further flare-up. See the separate leaflet called Moisturisers for Eczema (Emollients) for more details.
Short bursts of high-strength steroid as an alternative
For adults, a short course (usually three days) of a strong topical steroid may be an option to treat a mild-to-moderate flare-up of eczema. A strong topical steroid often works quicker than a mild one. (This is in contrast to the traditional method of using the lowest strength wherever possible. However, studies have shown that using a high strength for a short period can be more convenient and is thought to be safe.)
Short-duration treatment to prevent flare-ups (weekend therapy)
Some people have frequent flare-ups of eczema. For example, a flare-up may subside well with topical steroid therapy. Then, within a few weeks, a flare-up returns. In this situation, one option that might help is to apply steroid cream on the usual sites of flare-ups for two days every week. This is often called weekend therapy. This aims to prevent a flare-up from occurring. In the long run, it can mean that the total amount of topical steroid used is less than if each flare-up were treated as and when it occurred. You may wish to discuss this option with your doctor.
How do I apply topical steroids?
Topical steroids are usually applied once a day (sometimes twice a day - your doctor will advise). Gently rub a small amount (see 'Getting the dose right - the fingertip unit', below) on to areas of skin which are inflamed. (This is different to moisturisers (emollients) which should be applied liberally all over.) Gently rub the cream or ointment into the skin until it has disappeared. Then wash your hands (unless your hands are the treated area).
Getting the dose right - the fingertip unit
The amount of topical steroid that you should apply is commonly measured by fingertip units (FTUs). One FTU is the amount of topical steroid that is squeezed out from a standard tube along an adult's fingertip. (This assumes the tube has a standard 5 mm nozzle.) A fingertip is from the very end of the finger to the first crease in the finger.
One FTU is enough to treat an area of skin twice the size of the flat of an adult's hand with the fingers together.
Two FTUs are about the same as 1 g of topical steroid. For example, say you treat an area of skin the size of eight adult hands. You will need four FTUs for each dose. (This is 2 g per dose. So if the dose is once a day, a 30 g tube should last for about 15 days of treatment.)
The following are further examples:
Fingertip units and children
An FTU of cream or ointment is measured on an adult index finger before being rubbed on to a child. Again, one FTU is used to treat an area of skin on a child equivalent to twice the size of the flat of an adult's hand with the fingers together. You can gauge the amount of topical steroid to use by using your (adult) hand to measure the amount of skin affected on the child. From this you can work out the amount of topical steroid to use.
The following gives a rough guide: For a child aged 3-6 months
- Entire face and neck - 1 FTU.
- An entire arm and hand - 1 FTU.
- An entire leg and foot - 1.5 FTUs.
- The entire front of chest and tummy (abdomen) - 1 FTU.
- The entire back including buttocks - 1.5 FTUs.
For a child aged 1-2 years
- Entire face and neck - 1.5 FTUs.
- An entire arm and hand - 1.5 FTUs.
- An entire leg and foot - 2 FTUs.
- The entire front of chest and abdomen - 2 FTUs.
- The entire back including buttocks - 3 FTUs.
For a child aged 3-5 years
- Entire face and neck - 1.5 FTUs.
- An entire arm and hand - 2 FTUs.
- An entire leg and foot - 3 FTUs.
- The entire front of chest and abdomen - 3 FTUs.
- The entire back including buttocks - 3.5 FTUs.
For a child aged 6-10 years
- Entire face and neck - 2 FTUs.
- An entire arm and hand - 2.5 FTUs.
- An entire leg and foot - 4.5 FTUs.
- The entire front of chest and abdomen - 3.5 FTUs.
- The entire back including buttocks - 5 FTUs.
Using topical steroids and moisturisers (emollients) together
Most people with eczema will also use emollients. Emollients are different to topical steroids and should be used and applied in a different way. When using the two treatments, apply the emollient first. Then wait 10-15 minutes before applying a topical steroid. The emollient should be allowed to sink in (be absorbed) before a topical steroid is applied. The skin should be moist or slightly tacky, but not slippery, when applying the steroid.
Are there any side-effects from topical steroids?
Short courses of topical steroids (less than four weeks) are usually safe and cause no problems. Problems may develop if topical steroids are used for long periods, or if short courses of stronger steroids are repeated often. The main concern is if strong steroids are used on a long-term basis. Side-effects from mild topical steroids are uncommon.
Side-effects from topical steroids can either be local or systemic. Local means just affecting that bit of skin and systemic means affecting the whole person.
- A stinging or burning feeling when you first apply the treatment. This is quite common but improves as your skin gets used to the treatment.
- Thinning of the skin has always been considered a common problem. However, recent research suggests that this mainly occurs when high-strength steroids are used under airtight dressings. In normal regular use skin thinning is unlikely and, if it does occur, it often reverses when the topical steroid is stopped.
- With long-term use of topical steroid the skin may develop permanent stretch marks (striae), bruising, discolouration, or thin spidery blood vessels (telangiectasias).
- Topical steroids may trigger or worsen other skin disorders such as acne, rosacea and perioral dermatitis.
- Skin colour may change. This is more noticeable if you have dark skin.
- Hair may grow more on the area of skin being treated.
- Some people may develop an allergy to the contents of the treatment, such as any preservative used. This may irritate the skin being treated and make the inflammation worse.
Topical corticosteroid withdrawal
This may occur when prolonged treatment with a moderate or potent strength topical steroid is stopped. Symptoms may include red skin, burning pain or stinging, itch, skin peeling and excessive sweating. Symptoms may be mild and short-lived or may be severe and last for much longer. In some cases, severe symptoms may settle after several days or a few months, followed by a prolonged period of dry, itchy skin but with gradual improvement.
- Some topical steroid gets through the skin and into the bloodstream. The amount is usually small and usually causes no problems unless strong topical steroids are used regularly on large areas of the skin. The main concern is with children who need frequent courses of strong topical steroids. The steroid can have an effect on growth. Therefore, children who need repeated courses of strong topical steroids should have their growth monitored.
- Fluid collection in the legs.
- High blood pressure.
- Bone damage (thinning).
- Cushing's syndrome - this is a rare problem caused by high levels of a hormone (chemical messenger) in your blood. Symptoms include fast weight gain, skin thinning and changes to your mood.
A leaflet comes with each topical steroid and gives a full list of possible side-effects.
Two common mistakes when using topical steroids
Some people use too little
A common mistake is to be too cautious about topical steroids. Some parents undertreat their children's eczema because of an unfounded fear of topical steroids. They may not apply the steroid as often as prescribed, or at the strength needed to clear the flare-up. This may actually lead to using more steroid in the long term, as the inflamed skin may never completely clear. So, you may end up applying a topical steroid on and off (perhaps every few days) for quite some time. The child may be distressed or uncomfortable for this period if the inflammation does not clear properly. A flare-up is more likely to clear fully if topical steroids are used correctly.
Some people use too much
Only use topical steroids for eczema as directed by your doctor. Some people continue to use topical steroids each day in the long term after the eczema has cleared to 'keep the eczema away'. This is not normally needed. Some people with severe eczema may require continuous steroid treatment. However, this should be under the close supervision of a doctor. All people with eczema should use moisturisers (emollients) every day to help prevent further flare-ups of eczema.
Further reading and references
Eczema: Atopic Eczema; Primary Care Dermatology Society (PCDS), 2015 British National Formulary (BNF); NICE Evidence Services (UK access only)
Sheary B; Topical corticosteroid addiction and withdrawal - An overview for GPs. Aust Fam Physician. 2016 Jun45(6): 386-8.