Allergies are usually associated with the immune system, genetics, and environmental factors. Increasingly, however, another element is appearing in this puzzle: the gut microbiota. A review of studies published in the International Journal of Molecular Sciences suggests that small intestinal bacterial overgrowth (SIBO) may be associated with symptom exacerbation in atopic diseases, such as bronchial asthma, food allergies, or chronic urticaria.
The review article was prepared with the participation of scientists and students from Wroclaw Medical University, including members of the Student Scientific Society of Allergology and Internal Diseases.
The gut and the immune system
SIBO (small intestinal bacterial overgrowth) refers to excessive bacterial proliferation in the small intestine. It may cause gastrointestinal symptoms such as bloating, diarrhea, or abdominal pain. However, a growing body of research indicates that its effects may extend beyond the digestive system.
Disturbances in the gut microbiota may affect the immune system through the so-called gut–immune axis. As a result, intestinal dysbiosis may contribute to the exacerbation of atopic diseases affecting the respiratory, skin, or gastrointestinal tracts.
Analysis of available studies shows that positive breath test results for SIBO are more frequently observed in patients with:
- bronchial asthma,
- food allergies,
- mast cell activation syndrome,
- chronic spontaneous urticaria.
However, this does not mean that SIBO is a direct cause of these diseases.
–It is estimated that in the general population, SIBO occurs in up to approximately 20% of healthy individuals, while for allergy sufferers, there are no clear data. Most studies, however, indicate a correlation between a positive breath test result and allergy symptoms,- explains Dr. Krzysztof Gomułka, Assistant Professor at the Department and Clinic of Allergology and Internal Diseases at Wroclaw Medical University.
As the researcher emphasizes, much of the available data concerns children; therefore, further studies in adult populations are needed.
When can SIBO treatment help?
The relationship between SIBO and allergies may have practical implications for the treatment of certain patients.
–The greatest chance of symptom improvement after the diagnosis and treatment of SIBO may concern patients with bronchial asthma, food allergies, and chronic spontaneous urticaria,- says Dr. Krzysztof Gomułka.
The mechanism of this relationship may work in both directions. On the one hand, SIBO may lead to so-called “leaky gut,” which promotes inflammation and allergic reactions. On the other hand, chronic inflammation associated with atopy may disrupt intestinal function and promote bacterial overgrowth.
A warning signal
Diagnostics for SIBO are not yet standard in patients with allergies. However, there are situations in which it is worth considering.
–A warning signal may be a sudden worsening of the course of an allergic disease or the appearance of new symptoms despite ongoing treatment,- emphasizes Dr. Krzysztof Gomułka.
In such cases, a more thorough evaluation of the patient’s condition and an extension of diagnostics, including for SIBO, may be necessary.
A new direction in allergy research
Researchers emphasize that further studies are needed to better understand the relationship between SIBO and atopic diseases. If future results confirm this association, the diagnosis and treatment of gut microbiota disorders may become an important component of therapy for some patients with allergies.
This material is based on the article: https://doi.org/10.3390/ijms27041865
Authors: Michał Terlecki, Wiktoria Brzeczek, Martyna Kowalczyk, Emilia Kiełczyńska, Klaudia Kukla, Gabriela Osmulska, Krzysztof Gomułka
International Journal of Molecular Sciences, Possible Crosstalk Between Small Intestinal Bacterial Overgrowth (SIBO) and Atopic Manifestations—A Short Overview