What is an allergy?


Allergy knows no boundaries and affects differently people of all age groups, infants, children, teenagers, adults and the elderly.

Allergy, defined by the World Health Organization (WHO) as ‘immunologically mediated hypersensitivity,’ has been on the rise for a long time and it is estimated that over 20% of the world’s population suffers from IgE-mediated allergic diseases.

People with allergy react abnormally to normally harmless things. Contact with these makes their body react aggressively, producing in many cases so-called immunoglobulin (IgE) antibodies, and activating immune cells, such as eosinophils or mast cells. This usually happens after repeated exposure. The initial process, by which an individual becomes sensitive, is called “allergic sensitisation”. The offending substances are called “allergens”. The allergy symptoms are a consequence of the release of damaging substances from the activated cells. People who are predisposed to produce IgE antibodies and have allergy symptoms are called “atopic.”

The type of allergic reaction depends on the individual’s immunological makeup and the organ affected by allergy, i.e., the “target organ”). So, allergic people may have allergic rhinitis and asthma (target organ: upper and lower airways), conjunctivitis (target organ: the eye), eczema, urticaria and angioedema (target organ: the skin), and food allergy (target organ: all the above, plus in some cases the gastrointestinal tract). Even if allergic symptoms appear in these target organs, allergy is a systemic disease in which the whole defence system of the body is involved, although symptoms may appear in only one target organ. A person may have just one allergy or several and this may vary at any time during life. If the whole body suddenly responds to the allergen, there will be an acute, generalized allergic reaction, which is called “anaphylactic” reaction. Anaphylactic reactions may result in the drop of blood pressure, in which case we have an anaphylactic shock, which can be very severe and may even be fatal.

What is the impact of allergies on Europe?


It is estimated that 1 in every 2 Europeans will suffer from an allergy by 2015. Among all the different types of allergies, respiratory ones are the most common and affect around 20-30% of the Europeans.[1] Even when 113 million European citizens suffer from allergic rhinitis and 68 million from allergic asthma, allergic rhinitis often remains under diagnosed; approximately 45% of patients never received a proper diagnosis.[2] Early diagnosis is important to avoid the so-called “allergic march” – a sequence of increasing sensitisation to allergens and manifestation of allergic symptoms: food allergy, atopic eczema, and other types of allergies – to help people to manage and control their respiratory allergy and to limit the high burden on national economies. Indeed, during the launch event of the EFA Book on Respiratory Allergies at the European Parliament last November 2011 , it was shown that the estimated costs of untreated patients amounted to a reduction in performance at work by 10-30%, which is a monetary loss of 24-72 EUR per day. This is quite a contrast, compared to the cost of treatment, which is 1 EUR per day.[3]


Allergy and patient groups in your own language:


Belgique/België – Astma-en Allergiekoepel vzw, Prévention des Allergies absl
България – Асоциация на Българите Боледуващи от Астма
Česká republika – České iniciativy pro astma o.p.s. (ČIPA)
Danmark – Astma-Allergi Forbundet
España – Federación Nacional de Asociaciones de Enfermedades Respiratorias (FENAER)
France – Association Asthme et Allergies, Association Française pour la Prévention des Allergies (AFPRAL)
Ελλάδα -Áνοιξη
Lietuva – Asociacija alerginių vaikų klubai
Luxembourg – Prévention des Allergies absl
Nederland – Sctichting Voedselallergie, Vereniging voor Mensen met Constitutioneel Eczeem
Norge – Norges Astma- og Allergiforbund (NAAF)
Österreich – Österreichische Lungenunion
Polska – Polska Federacja Stowarzyszeń Chorych na Astmę, Allergię i POChP
Suomi – Allergia-ja Astmalitto
Slovenije Društvo pljučnih in alergijskih bolnikov Slovenije
SvenskaAstma och Allergi Förbundet
Suisse/Schweizaha! Allergiezentrum Schweiz/aha! Centre d’Allergie Suisse
United Kingdom – Allergy UK


[1] Last November 2011, EFA launched its “Book on Respiratory Allergies – Raise Awareness, Relieve the Burden” and the corresponding Call to Action at the European Parliament.
Erkka Valovirta, EFA Book on Respiratory Allergies – Raise Awareness, Relieve the Burden, 2011, available here
[2] Erkka Valovirta, op. cit., note 6.
[3] Report on the EFA Respiratory Allergy Book, Launch Event, available at:

EFA eZine Archive