Allergic disorders are among the most common problems seen by pediatricians and primary care physicians, affecting over 25% of the population in developed countries. In the most recent National Health and Nutrition Examination Survey, 54% of the population had positive test responses to one or more allergens. According to a recent National Center for Health Statistics survey, the prevalence of food and skin allergies has increased over the past decade; with prevalence in 2015 of 5.7% and 12%, respectively. While the prevalence of respiratory allergies has been stable, it is still the highest among children (10.1%). In children, asthma, allergic rhinitis, and atopic dermatitis have been accompanied by significant morbidity and school absenteeism, with adverse consequences for school performance and quality of life, as well as economic burden measured in billions of dollars. In this chapter, atopy refers to a genetically determined predisposition to develop IgE antibodies found in patients with asthma, allergic rhinitis, and atopic dermatitis.
ESSENTIALS OF DIAGNOSIS & TYPICAL FEATURES
The diagnosis of asthma is based on recurrent episodes of cough, wheezing, dyspnea, or chest tightness, with various triggers, most commonly respiratory infections, exercise, aeroallergens, cold air, and irritants. At least 80% of children with asthma have an allergic predisposition.
Chronic airway inflammation, variable expiratory airflow limitation, and bronchial reactivity characterize the disease, but presentation is heterogeneous, and course over time, especially in children, is variable as well. The clinical course can be subtle for some children, but the risk of a severe, even life-threatening, asthma-related event is present.
Assessment of severity can be challenging particularly if comorbidities and adverse effects of chronic disease and medications are present. Hence assessment of control is helpful when treatment changes are being made.
The mainstay of asthma management involves targeting the inflammatory response and bronchoconstriction, avoidance of known triggers, identification of early warning signs, and creating an appropriate action plan. Regular assessment of response and control is necessary to prevent consequences of either poor disease control and medication side effects.
Due to the heterogeneity of asthma pathogenesis and still inadequate control found in some children with asthma-causing emergent health care utilization and school absences on regular controller therapy, add-on medications modulating specific immune responses can be helpful.
The Global Strategy for Asthma Management and Prevention 2014 (www.ginasthma.org) report offers a new definition of asthma as “a heterogeneous disease, usually characterized by chronic airway inflammation. It is defined by the history of respiratory symptoms such as wheeze, shortness of breath, chest tightness, and cough that vary over time and in intensity, together with variable expiratory limitation.”
Asthma is the most common chronic disease of childhood, affecting 6.2 million children in the United States. While current prevalence rates for asthma had increased in the past decade, there has been an indication of a decrease in prevalence since 2011 (most recent estimate in children <18 years is 8.4%). At least half of persons with current asthma reported having had an asthma attack in the past year. Gender, race, and socioeconomic disparities in the prevalence of asthma exist: (1) More boys than girls are affected in childhood; (2) Higher percentage affected among black children compared to Hispanic and non-Hispanic white children; (3) Children belonging to poor families are more likely to be affected.