Allergic airway diseases in childhood – marching from epidemiology to novel concepts of prevention

Abstract

In the past years, a wide range of epidemiological, clinical, and experimental studies have produced remarkable advances in the field of respiratory allergies in childhood. By the recent investigations on epidemiological trends, risk factors, and prevention of asthma and allergic rhinitis, various exiting concepts have been challenged, and novel innovative approaches have been developed. Pediatric Allergy and Immunology (PAI), with a number of highly relevant contributions between 2010 and 2012, has become an important forum in this area. The prevalence of asthma in some developed countries may have reached a plateau, while in developing countries, where the prevalence was previously low, allergic diseases are still on the increase. A wide array of risk and protective factors, including hygiene, infections, outdoor and indoor air pollution, allergen exposure, breast-feeding practices, nutrition, and obesity, play a multifaceted role in shaping the observed worldwide trends of respiratory allergies. Under the guidance of recent research, prediction and prevention strategies in the clinical practice are progressively changing, the focus moving away from avoidance of allergen exposure and toward tolerance induction.

Air pollution and allergic diseases

“…More recent investigators suggest that the asthma prevalence has plateaued in developed countries, while in developing countries, where the prevalence was previously low, allergic diseases are on the rise (15). Environmental changes are suspected to be the major driver of this increasing trend (16), with air pollution identified as an important extrinsic agent (17).…”

Allergology in Europe, the blueprint

“…This increase in knowledge has led to changes in diagnostic and therapeutic possibilities (e.g. new forms of immunotherapy, component‐resolved diagnosis), and it is expected that this tendency will continue; (ii) secondly, the increase in knowledge about environmental exposure (allergens and irritants) and the possibilities of primary and secondary prevention (benefits and risks of allergen avoidance, infant feeding, application of pro‐/prebiotics, risk of tobacco smoke, role of epigenetics); (iii) Thirdly, many epidemiological surveys have shown that the number of allergic patients in Europe and other developed and developing countries is increasing dramatically . A notable proportion of individuals with respiratory allergy in Europe are underdiagnosed, undertreated and dissatisfied with their treatment .…”

“…Up to about 50% of the European population has a tendency to develop allergic reactions. In many countries, more than 10% of all children are symptomatically allergic, while 30% may have had an allergic reaction at some time in their life . In several European studies, the prevalence of the (doctor's) diagnosis of asthma in children was shown to be around 5% of the population.…”

Non-allergic rhinitis in children: Epidemiological aspects, pathological features, diagnostic methodology and clinical management

“…Moreover, some authors suggested that LAR might be the first step of the natural history of AR, especially in polysensitized and young patients[37]. Indeed, some studies showed that children could develop systemic atopy to grass pollen only in the second or third season of nasal symptoms[38]. However, such a hypothesis upon LAR as an initial stage of AR needs to be tested adequately and immune processes might differ according to allergens.…”