Allergies: Causes, reactions and treatment options

Allergies are overreactions of the immune system to otherwise harmless substances such as pollen, pet dander, or certain foods. These reactions lead to symptoms such as itching and breathing difficulties. Treatment options include hyposensitization and medication, while preventative measures and a strong mucosal barrier can alleviate symptoms.

Allergies – briefly explained

Allergies are immune reactions to harmless substances such as pollen, pet dander, or certain foods. In sensitized individuals, the immune system recognizes these allergens as a threat and releases inflammatory messengers such as histamine, triggering symptoms such as itching, swelling, and difficulty breathing.

Allergies occur in two phases: First, the body becomes sensitized by producing antibodies against the allergen. A reaction then occurs upon repeated exposure. In severe cases, anaphylactic shock can occur, in which vital organs are deprived of nutrients, requiring immediate medical attention.

There are four main types of allergic reactions. Type I, the "immediate type," occurs quickly and severely and often involves pollen or food allergies. Types II to IV develop more slowly and involve reactions to medications or environmental allergens.

Various treatment options are available: Hyposensitization, a specific immunotherapy, helps gradually accustom the immune system to the allergen and reduce symptoms in the long term. Preventive measures such as protecting the mucous membranes and reducing allergen contact complement the treatment.

Medications such as antihistamines, cortisone preparations, or leukotriene receptor antagonists can relieve symptoms. Good mucous membrane care and proper nutrition support the immune system, control allergy symptoms, and strengthen the mucosal barrier.

What are allergies, allergens, antigens?

In allergology, allergies are defined as an immune reaction to normally harmless substances, called allergens or antigens. This reaction occurs when the immune system mistakenly recognizes a substance as a threat and reacts excessively. In doing so, it triggers various defense mechanisms that are normally used against pathogens such as viruses or bacteria.

Typical allergens include pollen, pet dander, house dust mites, certain foods, insect venoms, and medications. Contact with an allergen can trigger symptoms such as sneezing, rash, breathing difficulties, itching, or swollen mucous membranes in sensitized individuals.

The allergic reaction occurs in two phases: First, sensitization occurs, in which the immune system produces antibodies against the allergen without causing symptoms. Upon repeated exposure to the allergen, these antibodies are activated and release chemical messengers such as histamine, which cause the typical allergy symptoms.

In Germany, approximately 15% of adults have already been diagnosed with a pollen allergy. However, symptoms can vary in severity from year to year. In some cases, hay fever occurs suddenly and disappears completely after a while. Pollen allergies—and allergies in general—are complex "malfunctions" of the immune system, the origins of which are not yet sufficiently understood to predict whether a person with a certain predisposition will develop an allergy in a particular environment.

What happens in our body when we have an allergy?

An allergic reaction is essentially similar to a normal immune response. When the immune system recognizes a stimulus as harmful, it activates a defense mechanism to transport immune cells to the affected area as quickly as possible.

Inflammatory reaction to foreign bodies

This releases messenger substances such as histamine, which trigger the typical symptoms of inflammation: The blood vessels dilate, and the surrounding tissue swells and turns red. In hay fever, this leads to symptoms such as a blocked nose or watery eyes. Although these reactions seem annoying, they are designed to support the immune system. The inflammation causes more blood to flow to the affected area, which promotes the supply and exchange of defense cells, and the removal of harmful substances. In a normal course of events, the foreign body is neutralized, removed, and broken down by the immune system. The swelling gradually subsides, and the skin color returns to normal.

Allergic shock

In severe cases, the outcome may be different: In people with a strong tendency to allergies, the body releases excessive amounts of inflammatory mediators. This causes the blood vessels to dilate excessively, which, combined with fluid loss into the tissues, leads to a rapid drop in blood pressure and a lack of blood supply to vital organs. The body attempts to respond to this shock with measures such as an increased heart rate or the release of vasoconstricting substances, but if this condition persists for too long, it can become life-threatening.

Types of allergies, symptoms and treatments

Scientists divide allergic reactions into four subtypes, each involving different defense mechanisms. Roughly speaking, the time it takes for the allergic reaction to become noticeable increases from type I to type IV.

Type I is also known as the immediate type. Visible, severe reactions occur within seconds. Allergens that trigger this type can include insect venom, pollen, animal dander, food, and medications. This type is the most common and can cause anaphylactic shock.

Type II allergens occur within minutes or hours, but are rare. Here, the allergen triggers a defense reaction directed against the body's own cells. Allergens in this group are usually medications, but otherwise anything that causes the above-mentioned condition.

Type III develops into a problem after hours or months of exposure. Allergens here are viruses, microorganisms, or environmental allergens. The dangerous aspect of type III is the free-floating immune complexes that accumulate and clog the blood vessels.

Type IV allergy usually occurs on the skin as a contact allergy. The reaction to this form of allergy is very rapid, but the development of this allergy can take years (delayed onset). Unlike type I, where antibodies play a role, the initiative comes from specific defense cells, which, however, produce the same symptoms through their mechanisms.

Treat allergies?

There are various approaches to successfully treating allergies, ranging from alleviating symptoms to treating the underlying cause.

Hyposensitization (specific immunotherapy)

A promising treatment option for type I allergies, such as those found in hay fever, insect venom allergies, or house dust mite allergies, is hyposensitization. This method, also known as specific immunotherapy, aims to gradually accustom the immune system to the allergen and reduce the overreaction.

The therapy works by administering the allergen in increasing concentrations over a period of two to three years – either as an injection, drops, or tablets. This "learns" the body that the allergen is harmless, and the immune system reacts less strongly. In many cases, this treatment can permanently reduce or even cure allergy symptoms. It is particularly effective against insect venom, pollen, and mite excrement. Another advantage is that the success of hyposensitization can prevent cross-allergies.

However, the therapy does not work for every patient, and it is important to carry out the treatment regularly and over the entire period to achieve the desired effect.

Preventive measures

Allergies can be compared to sunburn: The more intense the contact with the allergen, the stronger the immune system's reaction. Just as you can protect yourself against sunburn, you can also take preventative measures against allergies.

Improve natural protection

The mucous membranes that line the eyes, nose, and respiratory tract play a crucial role in protecting against allergens. When healthy and intact, they can act as a natural barrier, trapping and removing allergens before they reach the immune system. Good mucous membrane care—for example, by regularly moisturizing them (e.g., nasal saline rinses) or avoiding irritants like smoke—can help maintain this natural protection and reduce the risk of allergic reactions.

Reduce allergen contact

If you already have an allergy, it's advisable to minimize contact with the allergen as much as possible. This includes avoiding environments where the allergen is commonly present. For pollen allergies, this means, for example, keeping windows closed during pollen season or using special pollen filters in your car. Those allergic to dust mites should use special bed linens and vacuum frequently to reduce allergen exposure.

Symptomatic treatment

If avoiding allergen contact and preventive measures are not enough, medications can be used to relieve symptoms:

Antihistamines: These medications block the action of histamine, a messenger substance released during allergic reactions that causes typical symptoms such as itching, sneezing, and swelling.

Cortisone-containing preparations: Cortisone can suppress inflammatory reactions and is administered in the form of nasal sprays, creams, or tablets. It is particularly effective for severe allergic reactions.

Leukotriene receptor antagonists: These medications prevent the action of leukotrienes, other messenger substances that play a role in allergic inflammation.

Mast cell stabilizers: They prevent mast cells, a type of immune cell, from releasing histamine when they come into contact with an allergen.

Allergic shock: emergency treatment

In rare cases, a life-threatening allergic reaction, anaphylactic shock, can occur. This condition requires immediate emergency medical treatment. Typical measures include:

Adrenaline injection: Administered in the form of an auto-injector (e.g., EpiPen), adrenaline helps stabilize blood pressure and dilate the airways.

Antihistamines and cortisone: These are given as additional support to control the allergic reaction.

Oxygen supply and fluid administration: These measures help to supply the organs with sufficient oxygen and stabilize the circulation.

Allergies and doctors

Allergy treatment is typically performed by various specialists, depending on the type and severity of the allergy. Here are the main physicians who may be involved in diagnosis and treatment:

Allergists: These are specialized doctors who specialize in the diagnosis and treatment of allergies. They perform allergy tests (such as skin or blood tests) to determine which substances a person is allergic to. Allergists also supervise specific immunotherapies (desensitization) and advise on preventive measures and appropriate medications.

ENT specialists (ear, nose, and throat specialists): ENT specialists can play an important role in treating allergies that affect the respiratory tract, such as hay fever or allergic asthma. They examine the mucous membranes of the nose, sinuses, and throat and prescribe nasal sprays, antihistamines, or other medications if necessary.

Dermatologists: Dermatologists are the right people to contact for allergic skin reactions, such as contact allergies or atopic dermatitis. They diagnose skin allergies and prescribe topical treatments such as ointments or cortisone preparations.

Pulmonologists (lung specialists): Pulmonologists treat allergic asthma or other respiratory problems caused by allergies. They perform lung function tests, monitor airway function, and prescribe asthma medications if necessary.

Family doctors: General practitioners or internists are often the first point of contact for allergic symptoms. They refer patients to a specialist or initially prescribe medication to relieve symptoms.

Pediatricians: Pediatricians are responsible for the diagnosis and treatment of childhood allergic diseases such as atopic dermatitis, food allergies, or hay fever. They work closely with allergists to find the best possible treatment.

Collaboration between different specialists is often necessary to treat allergies comprehensively and ensure the best individual therapy.

Allergies and nutrition

The body's mucous membranes provide natural protection against pathogens and foreign substances. They act as a barrier, intercepting and transporting allergens before they activate the immune system and trigger an allergic reaction. In a type I allergy, activated mast cells release histamine and other messenger substances, causing typical symptoms such as itching, sneezing, and watery eyes. Certain nutrients can help inhibit this process and alleviate allergy symptoms in various ways:

Strengthening the mucous membranes

A healthy diet can help keep mucous membranes intact and strengthen their barrier function. A balanced intake of vitamin A, omega-3 fatty acids, and zinc supports the regeneration and stability of mucous membranes. Foods such as carrots, fish, nuts, and seeds are good sources of these nutrients. A well-functioning mucous membrane can prevent allergens from entering the body and irritating the immune system.

Stabilization of mast cells

Vitamin C and calcium contribute to the stabilization of mast cells. They help seal the cell walls of the mast cells, making them less sensitive to allergens. A stabilized mast cell releases less histamine and other pro-inflammatory chemicals. Vitamin C is found in high amounts in citrus fruits, peppers, and berries, while calcium is found in dairy products, green vegetables like broccoli, and nuts. Adequate intake of these nutrients can reduce the intensity of allergic reactions.

Inactivation and degradation of histamine

L-Methionine: This essential amino acid promotes the breakdown of histamine in the body. It is primarily found in animal products such as meat, fish, eggs, and milk. Regular consumption can help reduce the histamine load in the body.

Zinc and vitamin B3 (niacin): These nutrients inhibit the release of histamine from mast cells. Zinc is abundant in foods such as meat, nuts, and legumes, while vitamin B3 is found in fish, whole grains, and seeds.

Vitamin C: In addition to its role in stabilizing mast cells, vitamin C promotes the faster breakdown of released histamine. It supports the immune system in controlling inflammatory reactions and alleviating symptoms.

Other useful nutrients

Vitamin B5 (pantothenic acid): Vitamin B5 is known to reduce the symptoms of inflammation. It is found in foods such as meat, eggs, whole grains, and legumes.

Manganese: A deficiency in manganese can increase the risk of allergies, as this trace element is involved in the formation of antioxidant enzymes that fight inflammation. Manganese is primarily found in plant foods such as grains, nuts, berries, and green vegetables.

Gamma-linolenic acid (GLA): This omega-6 fatty acid has anti-inflammatory properties and can help relieve allergy symptoms. It is found in plant oils such as hemp oil and evening primrose oil. Regular intake can reduce the body's tendency to inflammation.

Typical allergies and treatments

Here are some common types of allergies and their typical treatment options:

Allergies to grass

Grass pollen is one of the most common causes of hay fever, especially during the flowering season in spring and summer. Symptoms include sneezing, nasal congestion, itching, and watery eyes. Antihistamines, nasal sprays, and eye drops are used for treatment. For severe symptoms, desensitization can provide long-term relief.

Food allergies

Food allergies occur when the immune system recognizes certain food proteins as a threat. Typical symptoms include a rash, gastrointestinal upset, and difficulty breathing. Severe reactions can lead to anaphylactic shock, which requires immediate emergency treatment with adrenaline. Avoiding the offending food is the most important measure, and in mild cases, antihistamines can relieve symptoms.

Allergies to dogs, cats and horses

Pet allergies are often caused by proteins in saliva, dander, or urine. Symptoms are similar to those of hay fever (sneezing, itchy eyes) or skin rashes upon contact with the pet. Antihistamines and nasal sprays are used for relief. A long-term solution may be removing the pet from the environment, but in less severe cases, thorough cleaning of the living space and the use of air purifiers can also help.

Allergies caused by detergents

Detergents can trigger skin reactions such as redness, itching, or eczema. These contact allergies are often caused by fragrances or chemicals in the detergents. Using hypoallergenic, fragrance-free products and thoroughly rinsing laundry can reduce symptoms. Cortisone creams are prescribed for acute skin reactions.

Allergies with cough and allergic asthma

An allergic cough often occurs alongside respiratory symptoms and can be a sign of allergic asthma. This is caused by inflammation of the airways as a result of allergen exposure, such as house dust mite allergy. Treatment includes inhaled corticosteroids, bronchodilators, and antihistamines. In more severe cases or with long-standing asthma, long-term asthma therapy is used, often supplemented by desensitization.

Allergies and headaches

Allergies can cause headaches, especially sinusitis caused by hay fever or dust mite allergies. Treatment with antihistamines and decongestant nasal sprays can help relieve headaches by reducing the underlying allergic inflammation.

Eye allergies and eye drops

Allergic reactions of the eyes, such as itching, redness, and watering, are often triggered by pollen, dust, or pet dander. Antihistamine eye drops, decongestant eye drops, and sometimes cortisone-containing preparations help relieve symptoms. Regular cleansing of the eye area can also help prevent them.

Allergies during pregnancy

During pregnancy, existing allergies may become more severe or worsen. Treatment should be chosen with particular care to avoid risks to both mother and child. Many antihistamines are safe during pregnancy, but nasal sprays or cortisone-containing preparations should only be used after consulting a doctor.

Allergies in children

Children are particularly susceptible to allergies because their immune systems are still developing. Common allergies in children include hay fever, food allergies, house dust mite allergies, and atopic dermatitis. Treatment typically includes antihistamines to relieve symptoms, cortisone preparations for severe reactions, and, in some cases, specific immunotherapy (desensitization). Dietary or environmental adjustments may also be necessary to minimize exposure to allergens.

Allergy calendar

Allergy season begins in January with the flowering of hazel and alder trees, which can release pollen even at mild temperatures. Allergy sufferers should be alert to the first signs of pollen exposure, as it may already be in the air.

February brings increased hazel flowering and the beginning of the main alder flowering period. Allergy sufferers should prepare for the increased pollen count, as these plants are often the first allergens of the year.

In March, hazel and alder are in full bloom, while poplar, willow, and elm pollen also begin to spread. Ash trees also begin to flower. Pollen levels increase, and allergy sufferers should consider protective measures.

April is marked by the main flowering of birch, one of the most potent allergens. Oak and beech trees also begin to bloom, while grasses gradually enter the flowering season. Pollen levels often reach their peak.

In May, the main birch bloom is coming to an end, while oak and beech pollen dominate. Grasses are also now in full swing, further increasing the pollen load for allergy sufferers.

June is the peak of the grass pollen season, and rye is also in full bloom. Linden trees are beginning to bloom, releasing additional pollen into the air. Allergy sufferers should pay particular attention to their symptoms.

In July, pollen counts from grasses and rye decrease, while linden trees are in full bloom. These pollen can still cause allergic reactions, so it's important to remain vigilant.

In August, mugwort reaches its peak flowering and represents a high pollen load. In addition, the first pollen of ragweed (Ambrosia) begins to appear, which can be problematic for many allergy sufferers.

In September, the mugwort flowering season ends, while ragweed pollen reaches its peak. Allergy sufferers should be prepared for symptoms, as this pollen can be highly present in the air.

October marks the end of the ragweed bloom season. Although pollen counts decrease, humid weather conditions can leave fungal spores in the air, which can also trigger allergies.

In November, pollen levels are minimal, but fungal spores may still be present in the air, especially in humid weather. Allergy sufferers should still be cautious, as these can also cause reactions.

In December, pollen season is almost over. However, hazel and alder pollen may be present in mild weather. Allergy sufferers should keep an eye on weather conditions to avoid possible symptoms.

Frequently asked questions about allergies

What are the most common allergies?

The most common allergies include hay fever (pollen allergy), food allergies (e.g. to peanuts, milk), animal hair, house dust mites and insect venom.

How are allergies diagnosed?

Allergies are diagnosed through medical history, skin tests (prick tests) and blood tests (IgE antibody tests).

Are allergies hereditary?

Yes, genetic factors play a role. If parents have allergies, their children are more likely to develop allergies as well.

Can allergies be cured?

Some allergies, such as type I allergies, can be treated with hyposensitization. However, a complete cure is not always possible.

How can I treat allergies?

Treatments include avoiding allergens, taking antihistamines, nasal sprays, or in severe cases, immunotherapy.

What is anaphylaxis?

Anaphylaxis is a severe, potentially life-threatening allergic reaction that requires immediate medical attention. It can include symptoms such as shortness of breath, swelling, and a drop in blood pressure.

How can I reduce allergens in my home?

Frequent vacuuming, washing bedding at high temperatures, using air filters, and avoiding carpets can reduce allergens.

Can allergies disappear over time?

Yes, some allergies, especially food allergies in children, can go away over time. However, with other allergies, sensitivity may persist or change.

Why do people in industrialized countries seem to get allergies more often?

People in industrialized countries are more likely to develop allergies due to factors such as excessive hygiene, environmental pollution, changes in dietary habits, and less exposure to microbes during childhood.

How can you “prevent” allergies through healthy lifestyles?

Allergies can be prevented through a balanced diet, moderate hygiene practices, regular exercise, adequate sleep and stress management

Helpful links:

German Allergy and Asthma Association (DAAB): https://www.daab.de

Allergy Information Service: https://www.allergieinformationsdienst.de

Robert Koch Institute (RKI): https://www.rki.de

World Allergy Organization (WAO): https://www.worldallergy.org

American Academy of Allergy, Asthma & Immunology (AAAAI): https://www.aaaai.org