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, 46% of the population had positive test responses to one or more allergens. In children, the increased prevalence of asthma, allergic rhinitis, and atopic dermatitis has 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
- Episodic symptoms of airflow obstruction including wheezing, cough, and chest tightness.
- Airflow obstruction at least partially reversible.
- Exclusion of alternative diagnoses.
Asthma is the most common chronic disease of childhood, affecting over 7.1 million children in the United States. While current prevalence rates for asthma have increased in the past decade, the rate of asthma attack in the past year has been stable. One of 10 children has current asthma, and nearly two out of every three children affected have had at least one attack due to asthma in the past year. There is still a disproportionately higher health care utilization for asthma among children compared to adults affected by this disease. The burden of hospitalizations and emergency department or ambulatory and office visits, all indicators of severe asthma and risk factors for fatal asthma, impose significant costs to the health care 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 0.3 per 10,000 children with current asthma. The prevalence and 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 the majority of children with asthma. The principal allergens associated with asthma are perennial aeroallergens such as dust mite, animal dander, cockroach, and Alternaria (a soil mold). Rarely, foods may provoke isolated asthma symptoms.
About 40% of infants and young children who have wheezing with viral infections in the first few years of life will have continuing asthma through childhood. Viral infections (eg, respiratory syncytial virus [RSV], rhinovirus, parainfluenza and ...