Lakiea Wright, MD, MAT, MPH

Rising global temperatures are detrimental to not only our ecosystem but also our health by, for example, affecting the food supply and exacerbating diseases.

 Many studies have examined correlations between climate change and illness, from cardiovascular to respiratory disease. For allergies and asthma, emerging data are emerging about the possible effects of climate change, such as contributing to the onset of allergic diseases and asthma and creating conditions that worsen preexisting allergies and asthma.

Common environmental aeroallergens include pollen (tree, grass, weed), dust mites, mold, pet dander, and mouse. Environmental allergies are increasing, and it is estimated that up to 40% of children have symptoms of allergic rhinitis.

 In 2018 in the United States, there were 12 million visits for which allergic rhinitis was listed as the primary diagnosis.

 The rise in allergic rhinitis, commonly referred to as hay fever, is likely multifactorial, with climate change playing a pivotal role because of rising temperatures and rising carbon dioxide levels. With global warming and climate change, pollen seasons are longer, and more pollen is produced. Drastic swings in temperature may potentially make pollens more potent.

 It takes a few seasons of exposures for pediatric patients to develop allergic rhinitis, and risk of developing allergic rhinitis increases with age. A study in Europe, which modeled the effects of climate change, estimated that the number of patients with ragweed allergies would double in the next few decades in some regions.

 However, the effects of climate change and allergies are not limited to pollen.

Rising temperatures with increasing humidity also create an ideal breeding ground for mold.

 These conditions may contribute to more mold proliferation outdoors, which can have harmful health effects, especially for patients with asthma. In one study conducted in Chicago, asthma death rates were twice as high when the amount of 

The majority of asthma is allergic in the pediatric population. Multiple factors contributing to climate change and its effects on environmental allergens (eg, pollen and mold) may contribute to the development of asthma or worsening of symptoms. Some studies have demonstrated that climate change effects result in pollens that exhibit stronger immunoglobulin E binding, such as birch pollen, which may contribute to pollen-induced asthma exacerbations.

Along with global warming and climate change comes increased precipitation and flooding in some regions that can contribute to the proliferation of mold. Dampness is associated with mold proliferation, which is known to contribute to the development of asthma and worsening of asthma symptoms.

 In the aftermath of Hurricane Katrina, clinical studies demonstrated dwellings that were flooded had more mold, and implementing environmental remediation can help reverse the adverse respiratory effects.

After thunderstorms, asthma attacks and rates of asthma-related emergency department (ED) visits reportedly rise, a phenomenon termed “thunderstorm asthma.” It has been postulated that thunderstorm asthma is mainly driven by grass pollens, but some weed pollens and molds may play a role too. Larger particles of pollen and mold are broken into smaller particles that increase the concentration in the air. During thunderstorms, high winds allow the smaller particles to travel farther, and they may also travel deeper into the lungs and trigger asthma flares or respiratory symptoms.

With the rise in carbon emissions and other pollutants, these gases get trapped in the atmosphere and diminish the air quality. Major pollutants including nitrogen dioxide (NO

), ozone, diesel fuel exhaust particles, and particulate matter are all known to exacerbate asthma. Additionally, pollutants increase the permeability of the respiratory tract and may enhance the effects of pollens in susceptible individuals.

The increasing number of wildfires may also contribute to the development of respiratory disease, including asthma. This is particularly important in pediatric populations because of the small surface area of their lungs. Just a small amount of wildfire air pollution exposure can have dangerous effects on respiratory health. In a recent California study, particulate matter from wildfires was 10 times worse compared with ambient particulate matter exposures, resulting in more ED and urgent care visits for respiratory symptoms, including asthma flares, cough, and wheeze, in children.

 Additionally, recent findings published in

 linked wildfires with higher health care use for atopic dermatitis flares, and patients reported worsening pruritus

Health disparities and vulnerable populations

In the United States, there are striking health disparities across multiple health conditions. Communities of color and low-income communities suffer disproportionately from prevalence, morbidity, and mortality in many disease states. The effects of global warming and climate change will likely exacerbate health disparities. For instance, Black and Puerto Rican people have twice the asthma prevalence of White people, as well as higher asthma morbidity. Air pollution is known to exacerbate asthma, and there is higher exposure to ambient air pollution in communities of color. In a study conducted in California, despite fuel-efficient cars, traffic-related NO

 levels were higher in communities of color and low-income neighborhoods. Levels were 37% higher in non-White communities.

 Living conditions and the built environment play a pivotal role because, although climate change is a global phenomenon, vulnerable populations are disproportionately affected. For example, in communities of color, schools may have closer proximity to roadways, which multiple study findings show contribute to asthma morbidity. Prenatal exposure, early life, and childhood exposures to pollutants can have a synergistic effect on respiratory health.

Practicing clinicians play a critical role in helping to combat the climate change’s adverse health effects, starting with evaluating and treating patients. This extends beyond individual patient care and involves advocating for policies to reduce carbon emissions and greenhouse gases, with an emphasis on protecting vulnerable populations who experience the effects disproportionately and are at greater risk. At the individual patient level, it is important to take a detailed clinical history, including an environmental history to assess exposures and refer patients to appropriate resources, such as social workers or case managers (Table 1). Clinicians should also empower patients, providing them with strategies to mitigate environmental exposures (Table 2). It is also important to engage with both local and national medical societies to effect policy changes at all levels. For eg, the American Academy of Pediatrics has a climate change initiative which brings together members and partners to educate and advocate for policy changes to combat the risks of climate change on human health. The voice of the clinician needs to be heard to help ensure that the health needs of patients are at the center of efforts to combat climate change.

1. Poole JA, Barnes CS, Demain JG, et al. Impact of weather and climate change with indoor and outdoor air quality in asthma: a Work Group Report of the AAAAI Environmental Exposure and Respiratory Health Committee. 

 2019;143(5):1702-1710. doi:10.1016/j.jaci.2019.02.018

2. In-depth review of allergic rhinitis. World Allergy Organization. Accessed May 24, 2021. worldallergy.org/education-and-programs/education/allergic-disease-resource-center/professionals/in-depth-review-of-allergic-rhinitis#:~:text=Over%20400%20million%20people%20suffer,fifth%20most%20common%20chronic%20disease

3. Allergies and hay fever. Centers for Disease Control and Prevention. Accessed May 25, 2021. cdc.gov/nchs/fastats/allergies.htm

4. Lake IR, Jones NR, Agnew M, et al. Climate change and future pollen allergy in Europe. 

5. Baxi SN, Portnoy JM, Larenas-Linnemann D, Phipatanakul W; Environmental allergens workgroup. Exposure and health effects of fungi on humans. 

2016;4(3):396-404. doi:10.1016/j.jaip.2016.01.008

6. D'Amato G, Chong-Neto HJ, Monge Ortega OP, et al. The effects of climate change on respiratory allergy and asthma induced by pollen and mold allergens. 

 2020;75(9):2219-2228. doi:10.1111/all.14476

7. Aguilera R, Corringham T, Gershunov A, Leibel S, Benmarhnia T. Fine particles in wildfire smoke and pediatric respiratory health in California. 

 2021;147(4):e2020027128. doi:10.1542/peds.2020-027128

8. Fadadu RP, Grimes B, Jewell NP, et al. Association of wildfire air pollution and health care use for atopic dermatitis and itch. 

 Published online April 21, 2021. doi:10.1001/jamadermatol.2021.0179

9. Nardone A, Neophytou AM, Balmes J, Thakur N. Ambient air pollution and asthma-related outcomes in children of color of the USA: A scoping review of literature published between 2013 and 2017. 

 2018;18(5):29. doi:10.1007/s11882-018-0782-x

Articles

What does climate change mean for allergies and asthma in children?

Allergies, asthma, and climate change 

During the spring, exposure to pollen can trigger a range of symptoms in the nose, eyes, throat, lungs, or skin. Patients may refer to these spring allergy symptoms as hay fever. The classic presentation includes rhinorrhea, nasal congestion, sneezing, and/or nasal itching which are characteristic of allergic rhinitis, or watery itching eyes which are characteristic of allergic conjunctivitis.

 In addition, patients may present with cough secondary to postnasal drip or cough equivalent asthma, as allergens including pollen are common triggers for asthma.

 Finally, patients may present with a sore throat from postnasal drip or oral itching from pollen food allergy syndrome due to cross reactivity between pollen and food.

Patients with spring allergies may have common physical exam findings:

allergic shiners (dark circles around the eyes)

allergic salute (habit of wiping or rubbing the nose)

allergic crease (dark line at the bend of the nose)

rash around the eyes due to rubbing (periorbital atopic dermatitis)

Allergic rhinitis is the most common cause of chronic nasal congestion affecting 7.2% of US children annually. According to a 2014 National Health Interview Survey, 5.2 million children reported hay fever in the past 12 months.

Children with certain risk factors are more likely to have allergic rhinitis. These include a family history of atopy, and other allergic diseases such as asthma and atopic dermatitis.

Allergic rhinitis symptoms can be triggered by one or more allergens. When the body is exposed to a substance it perceives as foreign, such as pollen, it responds by producing specific immunoglobulin E (IgE) antibodies. The antigen or allergen binds to the antibodies that cross link on allergy cells, such as mast cells, releasing chemical mediators such as histamine. Histamine triggers symptoms, including sneezing and a runny, itchy nose.

Temporal classification of allergic rhinitis

There are generally 3 pollen seasons, which vary based on the climate in which the patient lives. Spring is significant for tree pollen, including birch, cedar, cottonwood, and pine. However, in late spring, grasses, such as Timothy, Johnson, and rye, begin to pollinate. Toward the end of summer, ragweed pollen appears and continues into fall, along with outdoor molds. Environmental irritants, among them cigarette smoke, perfumes, diesel exhaust, and cleaning products, can also trigger nasal symptoms.

The diagnosis of allergic rhinitis is largely based on clinical history and physical exam. However, when patients do not improve with over-the-counter medication, the diagnosis is uncertain or the allergic trigger needs to be identified for targeted environmental mitigation, allergy testing is recommended. Specific IgE allergy testing, a blood sample or skin prick, helps aid in the diagnosis of allergies. A diagnostic algorithm for rhinitis is presented in 

The diagnosis of allergic rhinitis accounts for the timing, frequency or duration, and severity of symptoms. Classifying the disease is important to guide its management.

Allergic rhinitis classified by frequency and duration of symptoms is divided into intermittent and persistent. Intermittent allergic rhinitis has symptoms that last for fewer than 4 days per week or 4 weeks per year, whereas persistent allergic rhinitis symptoms last for more than 4 days per week and 4 weeks per year.

Allergic rhinitis classified by severity of symptoms is divided into mild and moderate/severe. Mild allergic rhinitis does not interfere with the patient’s quality of life.

 However, moderate/severe allergic rhinitis has symptoms severe enough to decrease quality of life, such as disordered sleep, impaired daily activities, and missed school and work days.

 Results from recent studies suggest that poorly controlled allergic rhinitis can negatively affect academic performance.

Further, it is important to note that approximately 30% to 50% of patients with chronic rhinitis may have a combination of allergic and nonallergic rhinitis, referred to as mixed rhinitis.

 Timely diagnosis and optimal management of allergic rhinitis is important to prevent complications, such as sinusitis, ear infections, chronic effusion, chronic headache, halitosis, dental problems, and sleep disturbances.

Sometimes it can be hard to tell the difference between allergies and viral illnesses, including coronavirus disease 2019 (COVID-19) infection. Many symptoms, such as nasal congestion, runny nose, cough, and headache, overlap, as illustrated in the National Center for Immunization and Respiratory Diseases’ Venn diagram (

 Therefore, it is crucial to keep COVID-19 infection high on the differential and to consider testing the patient.

Managing allergic rhinitis and environmental allergies involves a 2-fold approach: pharmacologic therapies and environmental mitigation strategies. As exposure to allergens in sensitized individuals promotes inflammation, using medications to treat symptoms and mitigating exposure to allergens are very important. For treatment of seasonal allergy symptoms, initiating treatment with intranasal steroids and/or oral antihistamines is recommended 1 to 2 weeks prior to the start of the season; this should be continued throughout the season. The primary treatment for allergic rhinitis is intranasal steroids. However, they may not be tolerated in young children. Long-acting, nonsedating oral antihistamines (cetirizine, levocetirizine, fexofenadine, or loratadine) may be used in combination with or without intranasal steroids.

 An antihistamine or mast cell stabilizer eye drops, such as olopatadine or inhaled corticosteroids, are the mainstay of treatment for allergic asthma but therapy may need to be adjusted as outlined in the National Institutes of Health’s National Asthma Education and Prevention Program guidelines.

 Treatment of pollen food allergy syndrome entails avoiding the “fresh” form of culprit food(s) referenced in 

, or other strategies such as peeling the skin or eating the cooked version. These strategies are typically tolerated.

NATURAL REMEDIES AND COMPLEMENTARY AND ALTERNATIVE MEDICINE

Many patients inquire about the use of natural remedies in the treatment of allergic rhinitis and allergic conjunctivitis. Rinsing the nasal passages with over-the-counter saline in a squeeze bottle or a neti pot, for example, can be effective as a means of washing away the allergens and mucus to help reduce symptoms. Using humidifiers to treat nasal congestion is generally not recommended because it creates an environment which promotes the proliferation of dust mites and molds. Acupuncture has not been commonly used in the pediatric population, but findings from small studies suggest it may be beneficial in the treatment of allergic rhinitis.

 Natural remedies for the treatment of allergic conjunctivitis include applying a cold compress to the eyes or using refrigerated artificial tears to remove allergens.

The majority of individuals with allergy symptoms are allergic to more than one allergen. Exposure to allergens should be minimized because there is a symptom threshold and reducing exposure lowers the risk of symptom exacerbation. For example, a patient may be sensitized to dust mites, mold, and animal dander with minimal symptoms year-round; however, in spring, exposure to birch pollen may cause exacerbations because they have reached their symptom threshold due to cumulative exposure to allergens and tree pollen, and thus “tip them over the edge.”

Pollens are microscopic and may be deposited on skin, hair, and clothing. Therefore, showering after coming in from outdoors is recommended. Trees tend to release the most pollen from 5 am to 9 am. Therefore, trying to minimize outdoor activities during the early morning hours may be helpful. Keeping windows closed in the car and home and wearing a mask with a small particle filter can also reduce pollen exposure. 

 lists environmental mitigation strategies for common environmental allergens.

Subcutaneous and sublingual are 2 types of immunotherapy available for aeroallergens. Subcutaneous immunotherapy works by introducing small amounts of allergen(s) in escalating doses until a maintenance dose is reached that helps to desensitize allergy cells. Typically, the patient receives a maintenance dose monthly for 3 to 5 years under the supervision of a physician. In recent years, there have been few new allergy medications. In 2014, sublingual immunotherapy tablets were approved for grass (ages 5-65 years) and ragweed (ages 18-65 years) pollens. In 2017, a dust mite sublingual tablet was approved for use in adults.

Sublingual tablets are not widely used in the pediatric population. One major barrier is the limited insurance coverage for these tablets. However, sublingual tablets may be used more frequently in the future as more children are formally diagnosed with common environmental allergens based on clinical history and confirmed with (blood sample or skin prick) allergy testing, and a more convenient home-based form of immunotherapy is desired.

If the patient does not improve with over-the-counter medications and there is evidence of sensitization to common environmental allergens on testing, consider referring to them to an allergist.1 Additionally, for patients who are atopic, a referral to an allergist to determine whether they are a candidate for allergen immunotherapy may be beneficial. Allergen immunotherapy is approved for the treatment of allergic rhinitis and asthma. For atopic patients with allergic rhinitis without preexisting asthma, subcutaneous allergen immunotherapy is indicated for the primary prevention of asthma.

Spring allergies are common in the pediatric population. Recognizing signs or symptoms, classifying the disease and implementing a 2-fold management approach is key to quality of life for patients. Although pediatricians manage most cases of allergic rhinitis in children, knowing when to refer to an allergist is important.

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It’s springtime, which means flowers are blooming and children sneezing. Here’s a quick refresher on seasonal allergy diagnoses and prescriptions.

Lakiea Wright, MD, MAT, MPH

Articles

Allergies, asthma, and climate change

Seasonal allergies: What every pediatrician needs to know