Treatments for allergies

What are allergies and what types are there?

An allergy is an exaggerated, specific defence reaction by the immune system to substances that are harmless in themselves, known as allergens. This reaction leads to the body becoming hypersensitive. This means that the immune system overreacts to proteins such as pollen, certain foods or animal dander, rather than ignoring them as it does in healthy people. Allergic reactions can occur in various parts of the body, including the skin, lungs, upper respiratory tract, gut or the mouth and throat, where they lead to chronic inflammation.

The course of allergies can vary greatly. Some people experience mild symptoms such as a slight cold, but severe, life-threatening conditions such as anaphylactic shock – which can be triggered by insect venom or certain foods – can also occur.

Experts distinguish between four types of allergies:

What is an allergic reaction and what happens in the body during one?

An allergic reaction involves an inappropriate response by the immune system to substances that are in themselves harmless (allergens). The following occurs in the body: upon first contact with an allergen, the immune system produces so-called IgE antibodies to defend against the allergen. When a person comes into contact with this allergen again, messenger substances such as histamine are released; these then interact with other substances in the body to trigger symptoms such as itching, a runny nose or a cough. Sometimes, an allergy can also be triggered by T-lymphocytes without the involvement of antibodies.

How are allergies treated?

The treatment of allergies is essentially based on three pillars. The first is allergen avoidance, which is, however, difficult to implement in the case of allergies such as pollen allergies. Symptomatic treatment involves the use of anti-allergic and anti-inflammatory medicines, including antihistamines and corticosteroids. The only causal treatment is hyposensitisation, also known as specific immunotherapy (SIT). In this treatment, the allergen to which the immune system overreacts is administered in gradually increasing doses in a controlled manner, in order to gradually accustom the body to it and reduce the allergic reaction in the long term.

What is allergen avoidance?

Allergen avoidance means deliberately avoiding allergens, i.e. those substances that trigger allergic reactions. This is a highly effective measure, because if the body has no contact with the allergen, the immune system cannot respond with an allergic reaction. Avoiding, or largely avoiding, allergens means, for example, refraining from eating foods that trigger an allergic reaction in an individual. However, not all allergens are easy to avoid. Pollen, for example, is difficult to control, and this is where allergen avoidance often reaches its limits.

Allergen avoidance is, however, easily achievable for the following allergies:

• Food allergy: avoiding specific foods.
• Animal dander allergy: Avoiding contact with certain animals.
• Contact allergy: Avoiding trigger substances such as certain personal care products or costume jewellery.

Allergen avoidance offers limited help with a house dust mite allergy. To alleviate symptoms, there are special covers (encasings) for bed linen and mattresses, which prevent contact with the allergy-triggering mite faeces.

What medicines are available and what are they used for?

Antihistamines

These medicines relieve mild to moderate symptoms in allergic conditions where the release of histamine plays a significant role, as they reduce the effect of histamine on histamine receptors. Antihistamines play a key role in the treatment of allergic rhinitis, allergic conjunctivitis (e.g. due to hay fever, animal hair allergy, house dust mite allergy), urticaria (hives), angioedema, certain drug allergies, itching (particularly in atopic eczema) and anaphylaxis. They are available as nasal sprays, eye drops, tablets, oral drops, oral solution and injections.

Corticosteroids (cortisone)

These are synthetically produced forms of cortisol, a hormone that plays an important role in the human body. As medicines, they primarily act as anti-inflammatories and suppress the immune system’s inappropriate response. Corticosteroids are mainly used to treat inflammatory skin conditions such as contact dermatitis or atopic eczema (neurodermatitis), allergic rhinitis, house dust mite allergy, allergic conjunctivitis and allergic bronchial asthma. Corticosteroids are highly effective and are usually used for a short period before switching to other medicines. They are available in many forms, such as ointments, inhalers, drops, tablets or injections.

Leukotriene receptor antagonists

These medicines can relieve the symptoms of allergic asthma by reducing bronchoconstriction and mucus production. They are particularly useful as an adjunctive treatment for mild to moderate asthma when corticosteroids alone are not sufficient. They are available in tablet form.

Anticholinergics

These medicines cause the airways to widen and inhibit the production of secretions in the mucous membranes of the airways. They are often used for allergic asthma and other lung conditions, particularly in combination with other medicines or when corticosteroids are not sufficient. They are mainly available as powder inhalers or nebuliser solutions.

Cromones

These medicines are not as potent as corticosteroids and antihistamines, are very well tolerated and are used to treat mild allergic rhinitis and conjunctivitis, allergic asthma and, in some cases, food allergies. They are available as nasal sprays, eye drops, inhalation solutions, capsules and granules.

Calcineurin inhibitors

These are cortisone-free anti-inflammatory medicines that are similarly effective to corticosteroids but have fewer side effects. They are used to treat mild to moderate atopic dermatitis. They are available as creams or ointments.

Beta-2 sympathomimetics

These medicines dilate the airways and are particularly effective in the treatment of allergic asthma. They are available as sprays, solutions, metered-dose inhalers, and also as tablets or injections.

Biologicals

These medicines, which have only recently become available, block certain parts of the immune response and are sometimes used to treat atopic dermatitis, asthma and urticaria when other treatments have not been sufficiently effective.

Decongestants (also known as vasoconstrictors or alpha-sympathomimetics)

They reduce swelling in the nasal mucosa in cases of allergic rhinitis, take effect quickly and can provide short-term relief. They are available as nasal drops or sprays.

What is hyposensitisation?

Hyposensitisation (also known as allergen immunotherapy (AIT), specific immunotherapy (SIT) or allergen vaccination) refers to a course of treatment lasting at least three years, involving the repeated administration of allergen preparations. The aim is for patients to develop a lasting tolerance to the allergen. This therapy is intended to reduce the patient’s allergy symptoms, which in turn reduces the need for anti-allergy medication. In the long term, hyposensitisation aims to have a positive impact on the course of the allergic condition. The long-term aim is to positively influence the course of the condition, so that, for example, asthma is less likely to develop following hay fever, or the symptoms disappear completely.

How does it work?

At the start of hyposensitisation, patients are administered a very small amount of an extract derived from an allergen. This dose does not yet trigger an allergic reaction, but it activates the immune system to produce antibodies, messenger substances and cells. This, in turn, blocks the intensification of the immune response caused by the allergens and reduces the inflammatory reaction. Over the course of the treatment, the amount of allergen administered is gradually increased until the highest dose – known as the maintenance dose – is reached. This process helps the body develop a tolerance to the allergen.

What options are available for hyposensitisation?

There are three forms of hyposensitisation – using drops, injections or tablets. A distinction is made between:

• Sublingual immunotherapy (SLIT): Here, the allergen extract is absorbed via the mucous membrane of the mouth in the form of a liquid solution or tablet.
• Subcutaneous immunotherapy (SCIT): In this method, the allergen extract is administered by a doctor as an injection.
• Oral immunotherapy (OIT): Here, the allergen extract – for example, in powder form – is swallowed.

Which allergies can desensitisation help with?

Desensitisation is particularly effective for immediate-type allergies, in which IgE antibodies play a key role in the development of the reaction. This treatment is the primary course of action for insect venom allergy, but can also be used for urticaria, allergic conjunctivitis, pollen allergy, allergic asthma, house dust mite allergy or certain food allergies.

What are the risks and side effects of hyposensitisation?

Desensitisation is generally well tolerated. With injections, local, rapidly resolving reactions such as redness or swelling at the injection site may occur. With other forms of desensitisation, local symptoms such as a tingling sensation in the mouth and throat may occur initially, but these usually subside after two to three weeks. Severe allergic reactions, such as anaphylaxis, are very rare.

Which doctor carries out desensitisation treatment?

Desensitisation is carried out by doctors with additional qualifications in allergology. These usually include ENT specialists, dermatologists, respiratory specialists or paediatricians. There are also specialist allergy clinics.

How much does hyposensitisation cost?

The cost of hyposensitisation is very high, but health insurance funds will cover it if it is medically indicated.

What complementary medicine options are available for treating allergies?

There are numerous complementary medicine approaches to treating allergies, although these are usually used to supplement conventional medicine. For example, there are good study results for acupuncture in the treatment of allergic rhinitis (hay fever). Kneipp therapies, phytotherapy (treatment with medicinal plants), balneotherapy (treatment with baths containing active ingredients), climate therapies, breathing and relaxation exercises, or specific dietary changes can also often produce positive effects.