Allergy is one of the most common diseases in children and the incidence is increasing. I out of 4 children is allergic. Most allergic children have non-allergic parents. If you or your child suffer from itching eyes and a stuffed or running nose, it’s easy to suspect allergy. But allergy to what? Is it one allergy or several? How serious can potential reactions become?
What’s an allergy?
An allergy is a hypersensitivity reaction initiated by immunological mechanisms to a substance or substances that are normally harmless. Allergy can be antibody- or cell-mediated. In the majority of cases the antibody typically responsible for an allergic reaction is called Immunoglobulin E (IgE). These individuals may be referred to as suffering from an IgE-mediated allergy. Allergens in the air – like pollen, house dust mite, mould, and cat or dog dander – can trigger a variety of symptoms, including sneezing, runny nose (Rhinitis), or itchy /watery eyes. Allergens can also trigger an asthma attack in someone with asthma and allergies (allergic asthma).
Allergic disease may become chronic causing not only a physical but also a social handicap. Correct diagnosis is a prerequisite for understanding the disease and for appropriate treatment.
Allergens add up!
Although a few patients are allergic to just one substance (for example dog dander or Bermuda grass) and react whenever they come near that animal or plant, most patients are sensitive to more than one thing. For these patients, symptoms appear only when they are exposed to two or more allergic triggers at once. In these cases the effects are cumulative, in other words, they add up! These patients may not show symptoms until their total exposure to allergens pushes them over the symptom threshold. Experts believe that by knowing which allergens patients are sensitive to and by avoiding or reducing exposure to such substances, patients can help to reduce their symptoms. Medical treatment and immunotherapy will also be more effective when exposures to causative allergens are reduced.
Relevant allergy symptoms:
- Gastrointestinal symptoms that may extent to the mouth and lips
- Dry itchy skin (Eczema) (1 out of 3 children is allergic)
- Rhinitis (7 out of 10 children are allergic)
- Wheeze/asthma (2 out of 3 children are allergic)
- Recurrent ear infections
Why should allergy tests be done?
If it is allergy, then the offending allergen should be identified:
- To be able to provide optimal and effective therapy
- To identify and avoid appropriate substances (trigger allergens)
- Identify allergens for immunotherapy (desensitization) since symptomatic treatment may not be enough
- Identify patients whose symptoms cannot be attributed to allergy
- Prevent unnecessary therapy
- Prevent unnecessary allergen avoidance (food avoidance, animal removal etc.)
If it is not allergy,then further investigation is recommended to determine the true cause of the symptoms since the patient may not respond to treatment more relevant to allergic conditions.
Should my child be tested?
Allergy can both cause and contribute to the symptoms that lead to upper respiratory tract problems, skin problems or gastrointestinal problems and therefore is allergy testing a very important prerequisite for early and correct identification and diagnosis of allergy. There are a number of diseases similar to allergy that can have completely different causes altogether. Therefore, children with recurrent or persistent episodes of symptoms related to allergy should be tested for allergic disease. There is a widespread misunderstanding that infants and very young children cannot be tested. The fact is that there is no lower age limit. Children with persistent symptoms early in life need to be tested, including children experiencing severe allergic episodes.
An ImmunoCAP blood test can be performed irrespective of:
- Disease activity and/or severity
Which allergens should you test for?
The substances to which a patient is exposed will generally dictate the allergens to test for. Nevertheless, some substances or allergens are more common as cause of allergy than others. Factors to consider when selecting which allergens to test for are:
- Home environment – pets, hobbies, plants, grasses etc.
- Food ingested
- Type of symptoms
- Age of patient
- Geographical area where patient live (consider different allergens like trees etc.)
Why isn’t a one-time test enough?
Allergy is constantly evolving, therefor an IgE antibody test taken at one specific time will only show the disease status at that particular point in time. Allergy undergoes dynamic changes over many years and the term “Allergy March” is often used to describe this characteristic disease progression. During a typical Allergy March sequence, sensitization generally:
- Appear during specific age intervals
- Persist over a number of years
- Tend to spontaneously decrease with age (“outgrowing” allergy)
Only regular testing of specific allergens at specified intervals of time will provide the information needed to accurately follow disease development to help understand how their allergic disease may develop in the future.
A correct allergy diagnosis is built up step-by-step based on the patient’s symptoms, the case history and a physical examination.
With a precise and quantitative test such as an ImmunoCAP, IgE antibody formation can be detected at an early stage, even before clinical symptoms have evolved. This enables the physician to prescribe the best strategy for managing the disease and trying to avoid the development into a severe chronic condition.
If contact with allergens cannot be avoided, immunotherapy can be considered in school-age children. This type of therapy involves injecting increasing amounts of allergen into the patient to increase the threshold to that particular allergen. Benefits from immunotherapy have been demonstrated in allergy to insect venoms, pollens, mites, animals and moulds, when well characterized and standardized allergen extracts are used.
There is a slight but definite risk of an adverse local or systemic reaction. Therefore immunotherapy should only be carried out by qualified personnel.