Focus on Allergies: Causes, Effects, and Modern Treatment Options—An Expert Interview with Prof. Bergmann

Professor Dr. med. Christoph Bergmann is an outstanding otolaryngologist specializing in sleep medicine and allergology, whose extensive clinical and scientific expertise makes him one of Germany’s most respected specialists. In his private practice and as head of the ENT department at the RKM740 Specialist Clinic in Düsseldorf, he offers his patients highly specialized and individually tailored care. Prof. Dr. Bergmann’s practice focuses on the treatment of allergies, sleep disorders, nasal and sinus conditions, as well as functional and cosmetic rhinoplasty. His ability to combine medical precision with empathetic care has been recognized on multiple occasions through his inclusion in the FOCUS list of top doctors, particularly in the fields of nasal surgery, snoring surgery, and allergology.

The RKM740 Clinic, whose name refers to its geographic location at the 740th kilometer mark of the Rhine in Düsseldorf, stands for interdisciplinary and holistic medical care. Here, modern conventional medicine is combined with complementary approaches such as Ayurveda to offer patients comprehensive treatment. This philosophy is also reflected in Prof. Dr. Bergmann’s practice, which employs state-of-the-art diagnostic procedures and innovative therapies to promote the health and quality of life of his patients. Since 2021, Prof. Dr. Bergmann has been running his private ENT practice at RKM740 and is also a professor at the University of Duisburg-Essen, where he trains medical students in the field of otolaryngology.

In addition, he serves as the Düsseldorf Regional Chair of the Association of German Allergists (AeDA), as Secretary of the Working Group of the European Academy of Allergy and Clinical Immunology (EAACI), and as a member of the Examination Board of the North Rhine Medical Association and the Continuing Education Committee of the Medical Academy. His core medical areas of expertise include not only aesthetic and functional nasal surgery but also the treatment of allergic diseases, sleep disorders such as OSAS and insomnia, ear ventilation disorders, and the diagnosis and treatment of silent reflux using 24-hour pH monitoring. His patients also benefit from innovative therapies such as longevity infusions. Prof. Dr. Bergmann combines scientific excellence with a deep understanding of his patients’ needs.

The editorial team of the Leading Medicine Guide had the opportunity to learn more about allergies in a conversation with Prof. Dr. Bergmann.

Allergies are among the most common chronic conditions worldwide and can affect people of all ages. They occur when the immune system overreacts to otherwise harmless substances such as pollen, dust mites, or certain foods. This hypersensitivity can cause a wide range of symptoms, from mild itching to severe respiratory problems or anaphylactic reactions. Due to the influence of environmental factors, genetic predisposition, and increasing allergen exposure, allergies are on the rise worldwide and often present significant challenges for those affected in their daily lives. However, early diagnosis and modern treatment methods can help effectively alleviate symptoms and improve quality of life.

The development of allergies is influenced by a complex interplay of genetic factors and environmental allergens. 

“First, it is important to understand that the human body has various interfaces at the junction between the body and the environment. The first of these interfaces is the skin, which possesses a robust immune system. Other important barriers include the upper and lower respiratory tracts—the eyes also play a role, as foreign substances can enter through them. The third major interface, which is particularly large, is the gut. Regulation by the immune system takes place at all these interfaces, and an allergy is considered a misdirected reaction of this system. Many centuries ago, allergies were unknown; they only began to occur more frequently in the wake of industrialization and other developments in Western industrialized nations. Allergies—defined as excessive reactions of the immune system to substances that are actually harmless—were not yet fully understood at that time. It is only in the last 130 years or so that science has gained a more precise understanding of allergies, leading to the development of targeted therapies. This explanation makes it clear that allergic symptoms manifest primarily at the body’s interfaces, since this is where the immune cells are located. In people with allergies, these cells mistakenly identify harmless foreign substances or particles as dangerous and trigger an exaggerated immune response. In young children, this typically first manifests on the skin, while in later years the nose, eyes, and lower respiratory tract are increasingly affected. The lungs are rarely the first to be involved—rather, the allergy gradually progresses downward. This progression is known as the “allergic march”: Initially, the nose and eyes are affected, manifesting as rhinoconjunctival symptoms—that is, simultaneous inflammation of the nasal mucous membranes (rhinitis) and the conjunctiva of the eye (conjunctivitis). “These symptoms manifest as itching, swelling, edema, or a runny nose,” explains Prof. Dr. Bergmann at the start of our conversation, adding the following regarding climate change and hygiene:

“Since the late 1980s, there has been the hygiene hypothesis, which states that excessive hygiene underchallenges the immune system—a phenomenon observed particularly in industrialized countries. A study by pediatric allergist Professor von Mutius of Ludwig Maximilian University in Munich confirms that children who grow up on a farm or in rural areas in general have a five times lower risk of developing allergies later in life. This is because their immune systems are challenged more in those environments. T cells, particularly Th2 cells, play a crucial role in allergies. In people with allergies, these cells react to normally harmless substances such as pollen or dust mites as if they were a threat. They activate the immune system, which then produces IgE antibodies. These antibodies bind to cells such as mast cells, which release histamine and other pro-inflammatory substances upon renewed contact with the allergen. This leads to typical allergic symptoms such as itching, swelling, and breathing difficulties. Climate change is also altering the growing seasons. Nature is beginning to bloom earlier and more intensely, which also alters pollen counts. In this context, allergy sufferers may find it helpful to regularly check the German Pollen Forecast Service.”

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At the end of the 19th century, scientists and doctors began to study the immune system and its reactions to various substances more intensively. In 1906, the German immunologist Clemens von Pirquet coined the term “allergy.” He used the term to describe an unusual hypersensitivity reaction of the immune system to substances that are normally harmless to the body. Pirquet found that allergic reactions are triggered by the immune system, which reacts to environmental factors such as pollen, food, or insect venoms in an excessive and harmful manner.

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The ALEX study was conducted as a cross-sectional study between 1990 and 2000 and examined the association between early childhood exposure to environmental factors and the risk of developing allergies. The study included more than 2,000 children from various rural and urban regions in Germany, Austria, and Switzerland. The study showed that children who grow up in an overly sterile environment and have little contact with microbes, pollen, or dust are at a higher risk of developing allergies later in life. These findings support the “hygiene hypothesis,” which posits that the immune system is not sufficiently trained due to insufficient stimulation during childhood and subsequently reacts hypersensitively to harmless substances such as pollen or dust mites. The study thus demonstrates that contact with natural environmental factors is essential for the development of a healthy immune system.

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It is important for children to grow up in nature rather than in an overly hygienic environment, as exposure to natural environmental factors such as dust, pollen, and microbes strengthens the immune system.

A certain degree of exposure to these stimuli promotes the development of a robust immune system that learns to distinguish between harmless and harmful substances. Children who live in a natural environment have a lower risk of developing allergic diseases because their immune systems are regularly challenged. In an overly clean or sterile environment, these important stimuli that support the maturation of the immune system are often lacking. “As far as children are concerned, there is an important study by Du Toit et al. that was published in 2015 in the highly regarded New England Journal of Medicine. It showed that children who were given specific allergens, such as nuts or milk enzymes, in the form of baby food developed significantly greater protection against allergies than children who did not have this exposure. “The body must therefore learn to cope with foreign substances,” says Prof. Dr. Bergmann.

People with a family history of allergies or other atopic conditions such as asthma or atopic dermatitis have a significantly increased risk of also developing allergic reactions. Certain gene variants—such as those that regulate the production of immunoglobulin E (IgE)—promote an excessive immune response to allergens. “For example, if both parents have allergies, the child has an 80 percent chance of developing an allergy as well. If only one parent is affected, the probability is 50 percent, and if neither parent is affected, it drops to less than 20 percent. Therefore, it is particularly important to offer children starting at five months of age a varied diet of complementary foods—including allergenic foods—in addition to breast milk or infant formula,” recommends Prof. Dr. Bergmann.

The three pillars of allergy treatment: avoidance, medication, and immunotherapy.

“In any case, a patient experiencing an allergic reaction should take action—depending on the severity of the symptoms. There are three main pillars of therapy for managing an allergy. The first is avoidance, that is, avoiding the triggering allergen. Whether it’s an apple that causes irritation in the mouth or dust mites that are primarily found in the bed—appropriate measures can help. For dust mites, for example, it’s advisable to avoid organic bedding and instead use cold-foam mattresses and synthetic comforters. Allergy-proof bedding and air purifiers can also reduce allergen levels in the bedroom—which, by the way, is also beneficial for people with pollen allergies. The second pillar involves anti-allergy medication taken as needed. This includes antihistamines, which patients take when they are exposed to an increased risk of allergies, such as during birch pollen season. These medications interrupt the allergic reaction that leads to the typical symptoms. In addition, there are combined corticosteroid nasal sprays, which are very effective, as well as antiallergic eye drops. If the lungs are affected, inhalation sprays are also used. However, these measures only treat symptoms. To address the root cause of the allergy, the third pillar of treatment is crucial: specific immunotherapy, also known as desensitization or hyposensitization. This causal form of therapy gradually trains the immune system so that it no longer perceives the allergen as a threat. It is the only way to stop—or in some cases even reverse—the “allergic march” described earlier—that is, the progressive development of an allergy leading to allergic asthma. Such therapy extends over a period of three to five years and is administered either as monthly subcutaneous injections (SCIT) or as a daily sublingual tablet (SLIT). “It is one of the services covered by health insurance,” explains Prof. Dr. Bergmann.

Molecular allergy diagnostics has made significant progress in differentiating between types of allergies by identifying specific proteins (allergen components) that trigger an allergic reaction. 

“The initial consultation with the doctor always begins with a medical history, during which the doctor asks which medications the patient is taking, whether there are any general health issues, and what the family’s allergy history is. The medical history is then supplemented by allergy testing in the form of a skin prick test. A wide range of molecular allergy tests is now available, tailored to the most common allergenic proteins found in pollen, dust mites, mold, animal dander, or foods. Alternatively, a blood test can be performed to detect specific IgE antibodies if sensitization is present. Modern allergy diagnostics increasingly rely on molecular methods. Unlike traditional skin tests or blood tests, which measure the immune system’s overall reaction to an allergen, molecular diagnostics identify specific allergen components that trigger an allergic reaction. Over the past 20 years, numerous surface structures of allergens have been identified. Each allergen consists of several molecules, but not all of them trigger an allergic reaction. Some people react only to certain parts of the allergen, while others are sensitized to several components at the same time. For example, some people react to the feces of house dust mites, while others react to their exoskeletons. This more precise diagnostic approach allows for a more nuanced assessment of allergy triggers. In fact, up to 295 allergens can now be tested in a single blood test, making it easier to classify even previously unclear symptoms. This opens up new possibilities for personalized medicine,” explains Prof. Dr. Bergmann.

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One example of the application of molecular diagnostics is distinguishing between a true food allergy and a cross-reaction. For example, a person may be allergic to birch pollen and at the same time experience symptoms after eating apples—not because of a separate apple allergy, but because of similar proteins in both substances. In this case, molecular diagnostics can precisely determine whether the reaction is due to birch pollen or the fruit itself.

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The composition of the gut microbiome plays a crucial role in the development and progression of allergic diseases, as the gut is the body’s largest immune organ. 

There is a close connection between the gut microbiota and the immune system. A balanced gut flora helps regulate the immune system and maintain a healthy balance between pro-inflammatory and anti-inflammatory responses. Disruptions in the microbiome, also known as dysbiosis, can, however, promote the development of allergies and influence their severity.

“The importance of the microbiome in the gut, skin, mouth, lungs, and nose—that is, at all interface areas—has significantly increased in medicine. We are talking about several million bacteria with which we live in symbiosis. The ‘good’ bacteria support us through positive interactions with the immune system and help prevent disease. It has been found that the microbiome of people with allergies has gaps that are not present in non-allergic individuals. The first microbiological contact occurs during a natural vaginal birth. Children born via cesarean section have a higher risk of developing allergies because they had less contact with their mother’s bacteria. “This finding has led to the development of supplements such as probiotics for the gut or specifically for people with pollen allergies, to restore the balance between ‘good’ and ‘bad’ bacteria and alleviate symptoms,” said Prof. Dr. Bergmann.

The gut microbiome can be positively influenced through various measures to prevent allergic diseases or mitigate their progression. 

A balanced diet high in fiber—found in fruits, vegetables, whole grains, and legumes—promotes the growth of beneficial bacteria such as bifidobacteria and lactobacilli. Fermented foods such as yogurt, kefir, and sauerkraut also provide probiotic cultures that can increase the diversity of the microbiota. “In any case, consuming fast food or convenience products promotes allergies. It’s important to prepare food from fresh ingredients! Sugar should also be avoided as much as possible, especially refined sugar, since it acts as a growth promoter for bacteria. Another helpful tip is to spend plenty of time outdoors and get plenty of vitamin D!” advises Prof. Dr. Bergmann, and with that, we conclude our conversation.

Thank you very much, Prof. Dr. Bergmann, for this highly interesting and important information!