Allergy testing in children: why, who, when and how?

The aim of this paper is to establish evidence-based recommendations on allergy testing in children. Besides sound scientifically based recommendations for allergy testing, a well-organised cooperation between primary care physicians for children and specialists in allergy is crucial in order to ensure a high quality and effectiveness of allergy diagnosis and treatment to the benefit of the individual patient. It is our intention that these recommendations on allergy testing in children will be adopted by the European Society and implemented in all European countries according to local needs and possibilities. During the last decade, a new system for classification of levels of evidence and grading recommendations in evidence-based medicine has been developed. Originally, evidence classification was created for causal and intervention/treatment studies (1, 2). Based on a classification of studies in four categories of statements of evidence (I (highest)-II-III-IV) guidelines for treatment/intervention graded A (highest)-B-C-D have been developed. Typically, randomized placebo-controlled trials and meta-analyses of such trials got the highest statement of evidence (I) and accordingly the highest grade of recommendations (A). However, in many cases randomization is not possible and recommendations must be based on lower levels of evidence. Thus, for some areas of practice such as diagnostic tests, recommendations higher than grade B are unlikely because of the type of study that can feasibly be conducted in those areas (2). Recently two well-established systems for grading of evidence for diagnostic tests have been developed (3, 4). The prevalence of allergic diseases in childhood (atopic dermatitis, asthma, and allergic rhinitis and conjunctivitis) has increased considerably in developed countries (5, 6) in the last 20–30 years, and accordingly the need of allergy testing has increased (Table 1). In population-based studies a cumulative prevalence of allergic diseases in childhood around 25–30% has been reported, atopic dermatitis in 15–20%, asthma in 7–10%, and allergic rhinitis and conjunctivitis in 15–20% (5–11). In infancy the main symptoms of possible allergic nature are atopic dermatitis, gastrointestinal symptoms, recurrent wheezing, whereas bronchial asthma and allergic rhinitis and conjunctivitis are the main problems later in childhood (12, 13). Adverse reactions to foods, mainly cow’s milk protein and hen’s egg are most common in the first years of life, whereas allergy to inhalant allergens mostly occurs later (12, 14). Correspondingly, specific immunoglobulin E (IgE) antibodies against milk and egg are most frequent during the first 2–3 years of life, whereas IgE against inhalant allergens is predominant later in childhood (13, 15). Interestingly, IgE antibodies to allergens (hen’s egg white, cow’s milk) in infants A. Host, S. Andrae, S. Charkin, C. Diaz-V zquez, S. Dreborg, P. A. Eigenmann, F. Friedrichs, P. Grinsted, G. Lack, G. Meylan, P. Miglioranzi, A. Muraro, A. Nieto, B. Niggemann, C. Pascual, M-G. Pouech, F. Ranc*, E. Rietschel, M. Wickman Statement of The Section on Pediatrics, European Academy of Allergy and Clinical Immunology