Allergies now affect around a third of European children. They can manifest in a number of ways, including food allergy, asthma, eczema and hay-fever. An allergy develops when the immune system reacts to a harmless substance such as hen’s egg, cow’s milk, grass pollen or house dust mite. Allergy can cause both immediate reactions and more chronic irritation of the lungs, skin or stomach which may not be clearly related to a specific trigger.
In childhood, allergic diseases include a variety of symptoms from different parts of the body, with different symptom patterns at different ages. In infancy and early childhood the most frequent symptoms are eczema and recurrent wheeze. These are usually due to an inborn dryness of the skin or viral infections, respectively. However, young children with persistent severe symptoms should be tested for allergy, especially if they have parents or siblings with allergic disease. If an allergy contributes to the symptoms in this age group, it will usually be a food allergy although some young children with asthma symptoms or rhinitis may also have allergy to house dust mites or furry pets. In the older children, asthma and hay-fever predominate, and many of these children have allergy to especially airborne allergens such as house dust mites, furry pets or pollens.
Hay-fever or allergic rhinitis is an allergy that affects the nose. Typically children complain about an itchy, runny or blocked nose, often in association with itchy, red eyes. Sometimes they have nasal secretion to the throat, which can lead to coughing and confusion as to whether the problem is with the nose or with the lungs. There are a number of allergies that give rise to allergic rhinitis or hay-fever. Children with problems in the spring or summer typically are usually reacting to tree pollen or grass pollen respectively. Those affected mainly in the winter are usually reacting to house dust mite while other children may have problems all year round due to an allergy to furry pets. It is very important to determine which allergies are causing the problem so that these can be avoided. If avoidance isn’t sufficient, there is a range of effective and safe medication which is usually effective for most children with allergic rhinitis or hay-fever. For more severe problems, it may be possible to desensitize the child to the allergy to control their hay-fever or allergic rhinitis symptoms.
Other children with allergies develop asthma where they have difficulty in breathing because their airways become smaller. They may complain about tightness in their chest, cough, wheeze and breathing problems with exercise. Not all asthma exacerbations are caused by allergens; irritants such as cigarette smoke or viral respiratory tract infections can also trigger them. Nevertheless, the role of irritants as triggers must not make us forget that there may also be an allergy contributing to the over-reactive airways. Knowledge of an allergy will help the child to avoid the allergy triggers meaning that they will need less inhaled corticosteroid medication to control their asthma.
Food allergies only affect about one in fifty children, but for these children and their families, they can be a major burden. Typical food allergies are egg and milk that will often start in the first year of life, and peanut, fish and shellfish that start a little later. An allergic reaction may involve a nettle type rash or swelling around the lips or eyes; some children can develop more severe problems such as breathing problems or collapse. It is essential that a child with food allergy has allergy testing to identify the trigger food so that they know which foods to avoid in the future trying to prevent further reactions. They also need to know how to manage a reaction if they have another one. Many small children outgrow their food allergies and allergy testing can also be helpful to predict when this has happened.
The principle for allergy testing in children is the same as for adults. Most allergies can be found with a skin prick test or a blood allergy test. There is no lower age limit, neither for skin prick testing or testing by a blood sample. In case of food allergy the only reliable test is a diet and challenge test, in which the symptoms disappears when the child is fed a diet without the suspected food item and reoccur’s at a challenge test with intake of increasing amounts of the food under medical observation.
There is a considerable amount of research being undertaken across Europe into allergies to try and understand why they occur and how we can prevent them. Many of the members of the European Academy of Allergy and Clinical Immunology are actively involved in these studies and the Academy’s meetings provide a valuable opportunity for researchers and clinicians to discuss the results. The Academy is also involved in improving the clinical care of children with allergies with its ongoing postgraduate education programme.