Eczema: its causes, how to get relief from the itching, and the promise of new treatments
- Adele, the Duchess of Cambridge, Nicole Kidman and Brad Pitt all suffer from eczema, an irritation for which there is no cure
- Some sufferers have it in their genes, others get it from something that breaks the skin, such as ear piercings. New treatments offer them fresh hope
What do singer Adele, the Duchess of Cambridge, Kate Middleton, and actors Brad Pitt and Nicole Kidman have in common? Besides their fame and wealth, these big names suffer from eczema, a common skin condition characterised by unbearable itching, dryness, redness, and flaky skin. Eczema has no cure, and many sufferers have to deal with the symptoms for life.
There are several causes of eczema, the most common being atopic dermatitis and contact dermatitis, says Dr Adrian Wu Young Yuen, a specialist in allergy and immunology at the Centre for Allergy and Asthma Care in Hong Kong’s Central district.
Atopic dermatitis is a genetic condition, with the genes responsible for the barrier functions of the skin being affected. This results in increased loss of water from the skin, leading to dryness and skin discomfort.
Without these barrier functions, the skin also becomes more permeable to allergens such as dust mites and chemicals in skincare products and household detergents, thus increasing sensitivity to those allergens; it also becomes less resistant to infectious agents such as the Staphylococcus aureus bacteria, the herpes virus and certain fungi, which may lead to chronic inflammation followed by itchiness and scratching and a further breakdown of the skin’s barrier.
Long-term use of topical steroids may also weaken this barrier.
For contact dermatitis in patients who do not have this barrier dysfunction – that is, people who do not have atopic dermatitis – sensitisation usually starts with a breach in the skin barrier, such as an ear piercing or cosmetic treatments like laser or chemical peels, Wu adds.
The introduction of certain chemical allergens, like nickel (commonly used in ear piercings), somehow sensitises the immune system, priming it to respond to a wide range of substances and chemicals, such as metals, fragrances, plant extracts, preservatives and dyes. Patients with atopic dermatitis are, of course, already at a high risk of developing sensitivity to these substances.
To manage flare-ups and prevent them recurring, doctors tell eczema patients to avoid contact with whatever they are allergic to and avoid substances that easily cause sensitisation. Some patients are advised to have allergy tests – skin-prick tests for environmental allergens and patch tests for chemical allergens – to identify their allergies so that they can avoid specific allergens.
Eczema patients are also advised to use emollients to strengthen the skin barrier, rehydrate their skin with warm baths, and avoid long-term use of topical steroids, which are associated with thinning of the skin and other undesirable side effects. They are also advised to take bleach baths if Staphylococcus colonisation is present.
Bleach baths, which involve soaking in a bath of water with a small amount of common household bleach added, are believed to kill bacteria on the skin, helping to minimise symptoms associated with eczema like itchiness, redness and scaling.
In severe eczema cases, patients are urged to consider systemic therapy with immunosuppressive agents or biologics. So far, however, there is only one biologic approved for atopic dermatitis – dupilumab, says Wu. This biologic is thought to work by blocking the inflammation that causes atopic dermatitis.
Another form of eczema relief is showing hope – bacteria-based treatments. Described as something like probiotics for the skin, these treatments contain good bacteria, which are said to reduce the amount of bad bacteria on the skin. And, unlike eczema treatments that contain antibiotics, they don’t also destroy any good bacteria that are present.
Only a few trials using these treatments have been carried out so far. One clinical trial, done by researchers at National Jewish Health in the American state of Colorado, involved a cream containing beneficial bacteria applied to the skin. The good bacteria made natural antibiotics that killed the “bad”Staphylococcus aureus bacteria, thus restoring a healthy bacterial balance to the skin and helping to create that all-important barrier to keep harmful bacteria out.
Another trial involved spraying a solution containing beneficial bacteria on a common eczema “hotspot” – the inner elbows. Nearly all the eczema patients – made up of adults and children – showed improvements. The results of this trial were published in JCI Insight in May 2018.
While these good-bacteria-based treatments sound promising, Wu says he is not aware of these treatments being used outside experimental studies and stresses that it’s too early to determine their effectiveness.
Nevertheless, if these treatments do become available, they are expected to be a cheaper and more sustainable alternative to current eczema treatments – and without the side effects.
Eczema and psoriasis: What’s the difference?
Psoriasis and eczema are associated with genetic abnormalities in skin barrier function, but why patients develop one or the other is unclear. Symptomatically, psoriasis is minimally itchy, whereas eczema is very itchy. Psoriasis lesions have silvery scales and are often thickened.
Eczema is often caused by an allergic sensitivity to contact allergens (dust mites, chemicals) and microorganisms (Staphylococcus aureus); no cause has been found for psoriasis.
Psoriasis is associated with arthritis in a certain percentage of sufferers, whereas eczema is often associated with allergic conditions such as rhinitis, food allergy and asthma.