Clinical Guidance for Heat and Children with Asthma

This guidance document is intended to help support your conversations with children, teens, and their caregivers on the impact of heat on asthma. The information provided can empower them to take protective actions on hot days. While not every child or caregiver may be able to take all actions, each action can help children or teens with asthma stay healthy during hot days.

Balancing outdoor time with staying safe from the heat

Being outside can provide many benefits to children’s health. Hot weather, however, can create conditions that can harm children’s health, especially because children have unique sensitivities to heat exposure. Children’s developing minds and bodies may be more sensitive to higher temperatures than adults. Children may spend more time outdoors, have less control over their physical environments, less knowledge about the health effects of heat, and less ability to remove themselves from harm. Heat exposure can impair learning and physical development, compromise mental health, and worsen asthma comorbidities in children.

Heat, air quality, and asthma

Hot days can both directly and indirectly increase risk to asthma patients.

Hot days may contribute directly to asthma attacks through dehydration. Dehydration, and associated lactic acidosis and electrolyte imbalance, can result in more severe asthma symptoms.

Hot weather can increase levels of air pollutants, including ozone, fine particulate matter, and sulfur dioxide. These pollutants can trigger asthma attacks and increase the need for medical care. For example, heat fuels the creation of ground level ozone, or smog, formation.  In addition, hot days can be humid, and humidity can worsen lung function.

Pollen is another common trigger for asthma. Over the past several decades, the pollen season has lengthened by several weeks in many regions of the United States.

Hot and dry weather can increase the risk of wildfires. Wildfire smoke pollutants provoke asthma symptoms. During the heat season, exposure to multiple concurrent environmental hazards, including wildfire smoke, pollen, and flooding that can lead to mold, can result in children facing several simultaneous asthma triggers.

Children with asthma and special health care needs, including children with compromised lung function and other co-morbidities, such as obesity, may be more susceptible to harm from heat exposure and air pollution. For these children, a discussion about chronic condition management should include guidance on managing heat and air pollution risks while still achieving physical activity recommendations.

Children and teens with asthma may benefit from including steps to reduce heat and poor air quality exposure in both their Heat Action Plan and their Asthma Action Plan.

Heat, medications, and asthma

Medications that treat asthma and other health conditions can interact with heat. Many medications, including over the counter medications, can impair heat tolerance and the body’s ability to regulate its temperature. This can predispose people to heat illness during hot days.

Medications, such as some antihistamines, can decrease the body’s ability to sweat, and therefore to cool itself. Some medications can cause electrolyte and fluid imbalance as well as dehydration. Some medications used to treat Attention Deficit/Hyperactivity Disorder (ADHD) like methylphenidate directly increase body temperature, increasing heat intolerance. Dehydration can reduce kidney blood flow, resulting in kidney injury from nephrotoxic drugs such as non-steroidal anti-inflammatory drugs (NSAIDs). Dehydration can also increase blood levels of medications which may result in adverse events. Heat-induced poor air quality may increase medication needs in children with asthma. Lastly, many medications, including certain antibiotics, can increase sensitivity of the skin to the sun.

Proper storage of medications during hot days is important since heat exposure may directly compromise medications and medication delivery devices. For example, in temperatures above 120° F, which can occur inside a car trunk on a hot day, metered dose inhalers can burst. EpiPens may malfunction or deliver less epinephrine when exposed to heat. Insulin, which should always be stored in a refrigerator, may become less effective if left in the heat.

Medication regimens, including those listed in your patient’s Asthma Action Plan, should be carefully reviewed with attention to those that may affect heat tolerance or fluid balance. A plan should be made for any necessary medication changes to maintain asthma control on days with heat and poor air quality. The Heat and Medications page provides more information on medications and heat that can inform patient guidance.

Take these 5 steps to help patients and/or caregivers of children and teens with asthma stay safe on hot days and document them in a Heat Action Plan with your patients.