Childhood eczema – a condition that causes the skin to become inflamed, dry, itchy and bumpy – is a constant source of worry for parents.

Children can scratch until they bleed, they can’t sleep, and they may end up often skipping nursery or school.

When the child itches and cries uncontrollably, parents are at their wits’ end, not knowing how to pacify their young one.

The lives of the child and parents are seriously affected.

Conventional treatment includes applying topical corticosteroids and emollients to restore skin integrity.

While eczema can affect anyone at any age, symptoms usually appear during early childhood.

There is no cure for eczema, but the condition may improve after childhood.

However, 30% will persist into adulthood or even emerge suddenly for the first time in later life.

Globally, roughly one in five adults have some sort of skin allergy, hypersensitivity or eczema.

Of late, a number of studies have highlighted the close relationship between gut dysbiosis and a variety of skin conditions, including eczema, acne, urticaria, psoriasis and hair loss.

Gut dysbiosis is an imbalance in the composition and function of the microbiome.

It can involve a decrease in beneficial bacteria, an overgrowth of potentially harmful bacteria, or a reduction in overall microbial diversity.

The human gut microbiome refers to the trillions of microbes, such as bacteria, fungi and other microbes that live in our intestines.

This community of microbes is also known as the microbiota.

The gut microbiome is unique to each individual as infants inherit their first gut microbes during vaginal delivery or breastfeeding.

Later, diet and other environmental exposures introduce new microorganisms to your microbiome.

Some of these exposures can harm and diminish the microbiota.

The interrelationship between gut microbes and skin conditions is known as the gut-skin axis.

Atopic dermatitis, a common form of eczema, has been specifically linked to gut dysbiosis.

This imbalance, detected through stool samples, often involves a decrease in beneficial bacteria such as Bifidobacterium breve and Bifidobacterium bifidum.

More emerging evidence is also showing that the gut microbiota plays a crucial role in regulating the immune system.

‘Hyper-hygienic’ ways

The skin – our body’s largest organ – plays a vital role in the immune system by acting as a physical barrier against pathogens, as well as housing its own immune cells.An imbalance in our gut microbiome can have negative consequences on other organs, including the skin. — TNS

As 70% of our immune system lies in the gut, an imbalance in the gut microbiome will indirectly influence the immune cells on the skin as well.

Intent on investigating this link, a team of gut microbiome researchers from The Chinese University of Hong Kong’s (CUHK’s) Medicine Faculty set out to explore the burden of eczema in Hong Kong and its underlying causes in a large-scale study.

They analysed data from 1,152 children aged between one and four years, and found a 46% rise in the incidence of allergy in toddlers born in Hong Kong during the Covid-19 pandemic, compared to before the pandemic. 

By sequencing 700 infant stool samples, they also found that the amount of beneficial bacteria associated with immunity in the gut of babies born during the pandemic were less than in those born pre-pandemic.

The alarming findings were published last year (2024) in the journal Gut Microbes.

“We found babies born during the pandemic had something bad going on in their gut.

“There was a depletion in richness of microbiome diversity, even now after the pandemic.

“These babies were not exposed to normal bugs because it was a very sterile environment during Covid-19 – we wore masks, washed or disinfected our hands constantly and sterilised spaces.

“We also used a lot of antibiotics and socially isolated ourselves, which changed our immune system.

“Due to these reasons, we are now seeing an increase in skin allergy conditions in children,” explains study co-investigator and gastroenterologist Professor Dr Siew C. Ng.

This higher incidence of eczema correlated directly with a  72% drop in B. breve, a strain integral in helping the infant gut and immune system to develop and mature.

Extreme hygiene practices during the pandemic had literally wiped out B. breve, leading to weaker immune systems, higher risks of allergies and gut issues.

The team also found that pandemic-born babies were three times more prone to harbouring bad bacteria, such as Klebsiella pneumoniae, which are resistant to antibiotics.

Additionally, the mode of birth governs the type of bacteria found in the gut.

She explains: “Infants born vaginally may have Bifidobacterium and Lactobacillus strains, but if they came out via a caesarean birth, they would have acquired bacteria from the nurses’ skin, hospital bed sheets, air conditioner, etc.

“A common strain found here is Staphylococcus that can cause gut dysbiosis.

“Hence, caesarean babies are more likely to have eczema.”

ALSO READ: Rubbing mum's vaginal fluid on caesarean section babies helps gut health

Basically, how you were born and what you were fed makes a difference.

As previous research had already shown that breastfed babies had better balanced gut bacteria, the team decided to exclude them from their study.

Prof Ng, who is also the Medicine Faculty’s associate dean, says: “Gut microbes need to be happy to talk to your skin and brain, but if in your early life, you already don’t have enough good bugs and your immune system is imbalanced, then we’re going to see a higher rate of skin allergies in the future.”

She adds: “Unlike Lactobacillus, which you can get from foods such as yoghurt, B. breve is not easily obtained from the diet. 

“It’s usually from the mother and the environment, so the only way to get it is through oral supplementation.”

“We then took these babies with mild, moderate and severe eczema, and gave them a patented microencapsulated formula, which can withstand stomach acid.

“To develop the formula, we used Asian people’s data because our diet is very different from Caucasians, and artificial intelligence to pick out which bacterium was depleted in children or adults with eczema.

“Then we identified the right ratio.

"It contains B. breve and B. bifidum, the two most important strains for children to develop the immune system.”

Surprising discovery

After three months of daily supplementation, the researchers found that all the babies with moderate eczema had their condition turn mild and half of those with severe eczema had turned moderate.Prof Ng says our extremely hygienic environment during Covid-19 has led to a decrease in beneficial gut bacteria in early life. — FAIHAN GHANI/The Star

The subjects’ sleep patterns were much better, their quality of life improved and parents were delighted.

Says Prof Ng: “We checked their stool samples before and after supplementation, and discovered that not only were the Bifidobacterium strains higher, but surprisingly, other good bacteria also started blooming, so their gut ecosystem was richer.”

Based on metagenomic sequencing – the direct genetic analysis of genomes contained within an environmental sample – the researchers found an increase in 23 types of beneficial bacteria in the gut.

“These two strains actually do more than just colonise the gut; they changed the environment to become healthier, and that improved the immune system and reduced eczema,” she says.

The results of this study were published in the journal Scientific Reports last year (2024).

While some children started displaying symptoms again upon stopping the formula, others were fine and managed to wean off the formula.

“We’ve been following these children and are going to start a second clinical study soon. 

“I actually suspect we need to colonise these bacteria for a longer duration.

“Perhaps then they can reduce flare-ups, eliminate eczema or reduce reliance on steroids or biologics,” she says.

The formula is now available as probiotics in sachet form at selected Malaysian pharmacies.

Prof Ng, who has published over 350 papers in international journals, says that as we grow older, there is a drop in these two strains.

“We found that those lacking in Bifidobacterium strains are prone to certain illnesses and are more likely to be infected with Covid-19.

"When they get it, their symptoms are also more severe.

“It’s all to do with the immune system, although the virus is external.” she says.

Read StarHealth on July 13 (2025) for more on CUHK’s research on restoring the gut microbiota to address long Covid.