New insights from the EAACI Congress 2026 

At the recent European Academy of Allergy and Clinical Immunology (EAACI) Congress in Istanbul, researchers shared exciting new findings about something called the epithelial barrier. While this may sound technical, it affects many allergic conditions, including eczema (atopic dermatitis), asthma, food allergy, allergic rhinitis, and even some autoimmune diseases. 

The message from experts was clear: protecting the body’s natural barriers may be one of the most important ways to prevent and manage allergic disease. 

What is the epithelial barrier? 

The epithelial barrier is the body’s first line of defence. It includes the skin, the lining of the airways, and the lining of the gut. These barriers help keep harmful substances out while allowing the body to function normally. 

When the barrier is healthy, it protects us from irritants, allergens, infections, and pollutants. When it becomes damaged or “leaky,” substances can enter the body more easily and trigger inflammation and allergic reactions. 

Researchers increasingly believe that many modern allergic diseases begin with damage to these protective barriers. 

Why do some people develop eczema? 

Genetics play an important role. Researchers highlighted the importance of a gene called filaggrin, which helps maintain a strong skin barrier. 

People who inherit certain filaggrin gene changes have a much higher risk of developing eczema. However, genes alone do not tell the whole story. 

Environmental factors can make the situation worse. Studies have shown that children with filaggrin mutations who are exposed to hard water may be at even greater risk of developing eczema. Hard water appears to increase the amount of soap residue left on the skin, which can further damage the skin barrier. 

This is a good example of how genetics and environmental exposures work together to influence disease risk. 

Are everyday products affecting our barriers? 

One of the strongest themes of the session was the impact of modern environmental exposures, sometimes called the exposome. This refers to everything we are exposed to throughout our lives, from birth onwards. 

Researchers discussed evidence that certain ingredients commonly found in modern products may affect barrier health. 

Particular attention was given to sodium lauryl sulfate (SLS), a detergent ingredient used in some soaps, shampoos, toothpastes, and cleaning products. Studies have shown that SLS can damage epithelial barriers and promote inflammation, especially in susceptible individuals. 

Researchers also discussed emerging evidence that some food additives and emulsifiers may influence gut barrier health and the microbiome. While much more research is needed, these findings highlight the importance of understanding how environmental exposures interact with our bodies over time. 

Can eczema be prevented? 

One of the most encouraging findings discussed was the potential for prevention. 

The STOP AD study showed that early and proactive use of emollients (moisturisers) in infants at high risk of eczema may help reduce the likelihood of developing the condition. 

This supports the growing understanding that protecting the skin barrier from the earliest stages of life may have long term benefits. 

For families with a strong history of allergy, this area of research offers hope that some allergic diseases may be preventable before symptoms even begin. 

The important connection between the gut and the skin 

Scientists continue to uncover fascinating links between the gut microbiome and skin health. 

Beneficial gut bacteria produce substances known as short chain fatty acids (SCFAs), including butyrate. These natural compounds help regulate the immune system, strengthen barrier function, and may even reduce the growth of harmful bacteria such as Staphylococcus aureus, which commonly worsens eczema. 

Some beneficial bacteria, including Lactobacilli and Bifidobacteria, can also produce compounds that may help reduce itching and inflammation. 

The research reinforces the importance of a healthy and diverse microbiome in supporting overall immune health. 

What role does the environment play? 

Researchers highlighted several environmental factors that may influence allergy risk: 

• Air pollution may alter immune responses and increase allergic inflammation. 

• Chronic exposure to environmental toxins may contribute to barrier damage. 

• Stress during pregnancy may influence a child’s future allergy risk through effects on the developing immune system. 

• Climate, sunlight exposure, and geography may influence eczema rates around the world. 

Interestingly, ultraviolet (UV) light was shown to increase filaggrin production, providing one possible explanation for some geographical differences in eczema prevalence. 

Looking ahead 

The research presented at EAACI reflects a major shift in how scientists think about allergic disease. 

Rather than viewing conditions such as eczema, food allergy, asthma, and allergic rhinitis as separate problems, researchers increasingly see them as interconnected conditions linked by barrier dysfunction, immune responses, genetics, and environmental exposures. 

While many questions remain, the findings offer an encouraging vision for the future. By understanding how our genes, environment, microbiome, and immune system interact, researchers hope to develop more personalised approaches to prevention and treatment. 

What can patients do now? 

Although much of this research is still evolving, there are practical steps that may help support barrier health: 

• Follow a regular moisturising routine if you have eczema. 

• Use gentle skin care products that are suitable for sensitive skin. 

• Avoid over washing and harsh detergents where possible. 

• Maintain a varied and balanced diet that supports gut health. 

• Avoid smoking and minimise exposure to air pollution where possible. 

• Discuss allergy concerns with your healthcare professional and seek advice before making significant lifestyle changes. 

The science is becoming increasingly clear: healthy barriers are fundamental to healthy lives. Protecting the skin, gut, and airway barriers may play a key role in reducing the burden of allergic disease for future generations. 

Adapted from presentations delivered during the “Epithelial Biology from Early Development to Repair Mechanisms” session at the EAACI Congress 2026 in Istanbul. 

Reference STOP AD trial – https://pubmed.ncbi.nlm.nih.gov/35997592/