The Changing Climate of Allergy/Immunology Disorders

Mrs. C walks into the Allergy, Asthma and Immunology (A/I) clinic with two-year-old Stephen. Stephen is irritable and whiny. He is covered with a rash and is scratching himself. He has scabs with bleeding spots and some of them are oozing pus. Both mom and child look exhausted. Mrs. C says Stephen wakes up multiple times at night scratching. Mrs. C wants to know the allergic triggers that make Stephen itch all the time. She has seen him break out in hives after eating eggs. She has also noticed that his eczema gets worse after visiting grandma. Grandma has a cat. Stephen’s older sister has allergies in the fall and has asthma. Stephen’s brother has eosinophilic esophagitis and is on a severely restricted diet. Mom is worried that Stephen is at risk for developing the same disorders and would like to know what to do.

Stephen is an archetypal patient seen by an A/I specialist at Children’s Mercy Hospitals and Clinics in Kansas City. His presentation is consistent with national trends since about one in five in the US have allergic rhinitis, one in ten have asthma, one in five have eczema, and one in 15 have food allergies.¹ The constellation of symptoms is also very typical of the ‘atopic march,’ with atopic dermatitis (‘eczema’), allergic rhinitis (‘hay fever’) and asthma representing progressive phases of the atopic spectrum.

This scenario is different from what allergists encountered in their clinics a decade ago. At that time, the typical patient was 16-year-old Demita, showing up at the last clinic appointment of the day, wheezing up a storm. Demita was well over the ninety-fifth percentile for weight and had a Cushingoid appearance with a buffalo hump and abdominal striae. She was on daily low dose oral steroids and on that treatment regimen for as long as she could remember. If she tried to taper off the steroids, she would end up hospitalized with severe asthma exacerbations requiring high-dose oral/iv steroids, making her gain even more weight.

Today’s scenario is different for multiple reasons. First, there has been a definite increase in the prevalence and impact of allergic and immunologic disorders in the United States in recent years, with as many as 50 million (more than 20% of the population) suffering from them.¹ There has also been a change in the pattern of the allergies, with increasing numbers of children having atopic dermatitis and food allergies. An analysis of multiple US national surveys showed that food allergy in school-aged children increased 18% from 1997 to 2007.² Recent dramatic climate changes, hypothesized to be due to global warming, have also greatly impacted patients with A/I disorders. In addition to the weather changes affecting lives and property, there is increasing evidence that they are adversely affecting airborne allergens. There is emerging data that there is increasing mold and pollen production over longer seasons and change in the distribution of stinging insects that cause hypersensitivity reactions.³

Second, there have been remarkable strides in allergy and asthma care. We now have a much better definition and understanding of allergic triggers and mechanisms of allergy, and effective and relatively safe long-term controller medications. After obtaining exhaled nitric oxide testing⁴ to determine the degree of inflammation in her airways, Demita would have been started on daily controller medications such as inhaled cortico-steroids (ICS), combinations of ICS with long-acting beta agonists (ICS-LABA), leukotriene receptor antagonists and biological modifiers such as anti-IgE therapy.⁵ She would have an asthma action plan empowering her to step up her asthma control medications at the first sign of exacerbation.⁶ Her allergic rhinitis would be controlled by newer generation non-sedating antihistamines, intra-nasal steroid nose sprays and evidence-based therapeutic concentrations of allergen immunotherapy extracts. She might have been given the option of sublingual immunotherapy. She likely would have had a home environmental assessment done to identify and manage her triggers. She might have even been offered the option of pharmacogenetic testing for ADRB2 genotype to determine her response to bronchodilators, CRHR1 genotype testing to ascertain response to inhaled corticosteroids, and testing of polymorphisms within the leukotriene pathway to find out her response to montelukast, as discussed in the accompanying article “The Impact of Pharmacogenetics in the Treatment of Allergic Disease and Asthma” by Jones.⁷

Third, there have been tremendous advances made in Allergy diagnostics. For instance, Stephen will have the opportunity to identify his allergen triggers either by skin percutaneous test or by blood tests as described in the accompanying article on “Appropriate Allergy Testing and Interpretation” in this issue by Portnoy.⁸ Depending on the results of the testing to the egg and peanut, he will be advised to avoid the foods completely or be given the option of undergoing a ‘baked egg challenge.’ He will be educated on anaphylaxis, prescribed injectable epinephrine to handle emergency reactions, and will be trained on how to read food labels to avoid inadvertent triggers. If his test results predict the likelihood of outgrowing his egg allergy, he may possibly undergo a super vised ‘oral challenge’ to scrambled eggs at the A/I office. If his test results suggest his egg allergy is persistent, he may be offered the option of undergoing a ‘desensitization’ procedure. His brother with eosinophilic esophagitis may be offered the opportunity of getting ‘patch testing’ done to identify culprit allergens. These and other issues pertaining to diagnosis and management of his food allergy are described in the article “Food Allergy: Practical Considerations for Primary Care” by Dowling.⁹

The scope of Allergy/Immunology however, is not restricted to allergic respiratory disease and food allergic disorders; exciting insights and breakthroughs have been made on other fronts. Significant inroads have been made into the management of rare genetic disorders such as the hypereosinophilic syndromes and hereditary angioedema disorders with deepening understanding of the biology of mediators involved in these disorders. The advent of newer biological agents has revolutionized care of these hitherto untreatable conditions. These and other therapeutic advances are detailed in this issue in articles “Approach to Patients with Eosinophilia” by Rosenwasser¹⁰ and “Angioedema: An Overview and Update” by Ciaccio.¹¹

Of course, the discussion of A/I disorders would be incomplete without elaboration of immunological disorders. In an elegant article on “Primary Immunodeficiency Update and Newborn Screening” by Amado¹² highlights strides made in diagnosis of severe combined immunodeficiency disorders using T cell reception circles (TREC) as a newborn screen. This exciting screening test, recommended by the Secretary of Health and Human Services, is not only cost-effective but a significant aid in early detection and prompt treatment of the potentially fatal ‘medical emergency,’ Severe Combined ImmunoDeficiency (SCID). Several states have already adopted the recommendation and Missouri anticipates adding this test to its repertoire in the near future.

Fortunately, while, there has been a rise in prevalence, range and severity of A/I disorders, there have also been parallel advances in understanding pathophysiology and management of these disorders. Studies have also shown that patients under the care of a trained allergist have better outcomes at lower cost because of fewer emergency department visits, fewer hospitalizations, increased productivity, improved quality of life and greater satisfaction with their care.¹³ Recent disturbing news about the impact of climate change on human life also underscores the role of the allergist as not only an expert on environmental allergens, but as a trained scientific observer who can interpret and translate data to appropriate care. The allergist can additionally help relay the environmental impacts in an understandable manner to colleagues, patients and the media.

However, the true breakthrough in the care of these patients comes from our collaboration with primary care physicians, the front-line foot soldiers. An arm-in-arm approach with ongoing engagement between A/I specialists and primary care providers is the best indemnity to ensure our patients with these disorders lead productive and healthy lives. PPIA simply means protection for your future.

Biography

Chitra Dinakar, MD, MSMA member since 2002 and Missouri Medicine Editorial Board Member, is Professor of Pediatrics at the University of Missouri-Kansas City, and Section of Allergy, Asthma and Immunology at Children’s Mercy Hospital and Clinics in Kansas City.

Contact: cdinakar@cmh.edu