What exactly is an allergy?

An excessive reaction of the immune system to substances that are actually harmless. The body fights substances such as pollen or certain foods as if they were dangerous.

Can allergies be treated?

Yes. After allergy testing, and depending on the findings, avoiding the trigger, hyposensitisation (a causal therapy) and symptom-relieving medicines come into question. You can find more on this under Allergy diagnostics and Allergy treatment.

When should I have an allergy investigated?

With recurring symptoms such as a runny nose, itchy eyes, skin rashes or reactions after foods, insect stings or medicines. Looking into it early helps to find the right treatment.

Allergic conditions

What is an allergy, and what forms does it take? An overview of hay fever, allergic asthma, food, insect venom and other allergies.

Overview

An allergy is an altered, excessive reaction of the immune system to environmental substances that are actually harmless. The immune system then no longer reliably distinguishes between harmful and harmless substances, so that pollen, foods, animal hair and much else can trigger a defensive reaction.

In Germany about one in three people is affected by an allergy at some point in life, and the trend is rising. The state of mind can influence allergic processes too: in people with the corresponding predisposition, stress at work or in private life can set off reactions or make them stronger.

Areas of application

Recurrent sneezing, runny nose or blocked nose
Itchy, reddened or watery eyes
Skin rash, itching or weals
Breathing difficulties, up to shortness of breath
Reactions after certain foods, medicines or insect stings

Risks & notes

Some allergic reactions can take a severe course: with an insect venom or food allergy, a life-threatening anaphylactic shock is possible.
If you suddenly experience shortness of breath, circulatory problems, dizziness or rapid extensive swelling, call the emergency number 112 at once.

Forms of allergic conditions

Hay fever – inflammation of the conjunctiva and mucous membranes triggered by tree, grass, blossom and herb pollen.
Persistent allergic rhinitis – triggered, for example, by animal hair, house dust mites or moulds.
Allergic asthma – can develop out of long-standing allergic rhinitis, with inflammation of the bronchi and shortness of breath.
Food allergy – a reaction to certain foods with swelling and itching; also a trigger of gastrointestinal complaints.
Urticaria (hives) – weals form on the skin; in severe cases there is a risk of allergic shock.
Drug allergy – frequently caused by antibiotics or by painkillers and anti-rheumatic medicines; usually as a skin rash, in rare cases also with severe reactions.
Sun allergy – an itchy skin rash after exposure to light.
Insect venom allergy – after a bee or wasp sting, for example; can lead to life-threatening anaphylactic shock.
Atopic dermatitis (eczema) – intensely itchy eczema as part of a complex clinical picture.

Frequently asked questions

What exactly is an allergy?: An excessive reaction of the immune system to substances that are actually harmless. The body fights substances such as pollen or certain foods as if they were dangerous.
Can allergies be treated?: Yes. After allergy testing, and depending on the findings, avoiding the trigger, hyposensitisation (a causal therapy) and symptom-relieving medicines come into question. You can find more on this under Allergy diagnostics and Allergy treatment.
When should I have an allergy investigated?: With recurring symptoms such as a runny nose, itchy eyes, skin rashes or reactions after foods, insect stings or medicines. Looking into it early helps to find the right treatment.