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 2009–2011 of 5% and 12.5%, respectively. While the prevalence of respiratory allergies has been stable, it is still the highest among children (17% in 2009–2011). 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.
Asthma is the most common chronic disease of childhood, affecting over 7 million children in the United States. While current prevalence rates for asthma have increased in the past decade (most recent estimate of 10%), the rate of asthma attack in the past year has been stable. 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.
There is still a disproportionately higher healthcare utilization for asthma among children compared to adults affected by this disease. Asthma health care encounters in primary care settings have increased over time; death rates and emergency department (ED) visits related to asthma have declined, and hospitalizations due to asthma have been steady. Hospitalizations and emergency department or urgent ambulatory or office visits, all indicators of asthma severity, impose significant costs to the healthcare system and to families, caretakers, schools, and parents' employers. Indirect costs primarily from loss of productivity due to school/work absences are harder to measure, yet considerable. Asthma remains a potentially life-threatening disease for children; the rate of asthma deaths was 28 per 1 million children with current asthma. Similar to disparities in prevalence, morbidity and mortality rates for asthma are higher among minority and inner city populations. The reasons for this are unclear but may be related to a combination of more severe disease, poor access to health care, lack of asthma education, delay in use of appropriate controller therapy, and environmental factors (eg, irritants including smoke and air pollutants, and perennial allergen exposure).
Up to 80% of children with asthma develop symptoms before their fifth birthday. Atopy (personal or familial) is the strongest identifiable predisposing factor. Sensitization to inhalant allergens increases over time and is found in ...