Stay Cool: How to Manage Autoimmune Flare-ups in Hot Temperatures

With summer around the corner, many people with an autoimmune disease are concerned that hot temperatures will trigger flare-ups. While warmer conditions and sunlight can provide relief for some people, heat and humidity can worsen signs and symptoms and lead to uncomfortable outbursts in others.

This article will discuss some of the diseases aggravated by high temperatures, why certain manifestations may occur more during the summer, and how people can avoid or manage flare-ups. Some of global warming’s effects on autoimmunity will also be discussed.

The relationship between heat and autoimmunity is poorly understood and supported by studies that often rely on self-reported signs and symptoms. Nevertheless, some autoimmune diseases clearly worsen with heat.

High temperatures, ultraviolet (UV) light, and humidity can trigger autoimmune flare-ups by inducing inflammation and affecting an already impaired immune system (1). However, some diseases will flare up more than others. Also, people with the same autoimmune illness may have different signs and symptoms in the warmer months. 

Many heat-related flare-ups are transient and disappear once relief is sought, but this also varies from person-to-person. For example, many people with multiple sclerosis may have temporary blurred vision, fatigue, dizziness, weakness, numbness and tingling in the extremities, and even cognitive problems (2, 3, 4). These issues occur because heat slows down impulse transmission in areas affected by demyelinating plaques, such as the brain and spinal cord (2, 3).

Research studies on the link between systemic lupus erythematosus and different weather conditions have revealed that warmer temperatures are associated with flare-ups that depend on what system or organ the disease attacks (5, 6). Some of the observed signs include increased fatigue, joint pain, rashes, and blood-related flare-ups, such as changes in cell counts and antibody levels (5, 6). The Lupus Foundation of America indicates that people with lupus are more sensitive to sunlight because the damaged cells are not cleared as promptly by an impaired immune system. This reduced clearance triggers immune reactions that lead to flare-ups (7).  

While warm weather and sunlight can often improve skin autoimmune disorders such as psoriasis, factors such as sunburn, injuries, and insect bites while spending time outside may trigger flare-ups that may cause plaques to become inflamed and painful (8, 9).

People living with different forms of arthritis may also be more susceptible to flare-ups in warmer times of the year. In the heat, joint pain and swelling may become more intense for some patients with psoriatic arthritis and rheumatoid arthritis (8, 10).

If you suffer from an autoimmune disease, you can still enjoy your summer by preparing for both outdoor and indoor activities and checking in with your doctor about prevention strategies.

Weather fluctuations often trigger flare-ups, so minimizing any sudden temperature changes helps reduce the risk of signs and symptoms.

Wear lightweight, loose clothing such as vests, pants, and dresses (2). Also, wear light scarves to protect sensitive areas such as the neck (2). Choose breathable fabrics such as linen or cotton, and consider long sleeves and pants in lighter colors that absorb less heat. Wear hats and sunglasses and limit sun exposure to the morning or later afternoon hours (2, 8).  

Enjoy outdoor swimming but take care to protect your skin from sunburn. Mineral-based sunblock options (with zinc or titanium) are best because they form a physical barrier, do not contain potentially irritating chemicals, and are typically fragrance-free (8). Wear protective clothing and apply insect repellent if you plan outdoor activities, such as hiking, to reduce the risk of injury and bites (9).

When the heat and humidity are excessive, spend time in air-conditioned environments. Ask your doctor about an air-conditioning equipment prescription as you may be able to deduct the cost when filing taxes (11). However, be mindful of colder environments and time spent in air-conditioned spaces because the cold and sudden temperature fluctuations may have undesired effects too. In addition, air-conditioning units dry out the air, so keeping your skin moisturized is essential. 

Drink cool beverages and popsicles to stay cool (2). Exercise outdoors early in the morning or later in the evening and keep indoor environments cool and ventilated. The National Multiple Sclerosis Society recommends cooling down strategies before and after exercising (2). For example, getting into a bathtub filled with lukewarm water and gradually adding cooler water over the course of about 30 minutes helps regulate body temperature (2). Dipping the lower limbs in cool water also helps before physical activity (4). Avoid places such as saunas and hot tubs and consider using cooling methods such as ice packs and other regional devices (4).

The American Academy for Dermatology suggests taking fewer baths and showers and washing with cool or lukewarm to prevent painful flare-ups for autoimmune diseases that affect the skin (12). Fragrance-free moisturizers help protect sensitive skin after washing (12).

Make an appointment with your doctor and discuss how to manage your specific autoimmune disease in higher temperatures, what precautions to take in different environments, or how to prepare for any upcoming vacation in hot climate destinations.

Research studies have revealed that the world’s warming climate may affect human health and worsen conditions such as allergies and autoimmunity (13, 14). Along with elevated air pollution and pollen levels, high temperatures and humidity may alter the microbial populations that live on different organs and systems in our bodies (14).

For example, the microorganisms of the skin, collectively known as the cutaneous microbiome, function as a barrier against illness and injury. When factors such as heat disrupt that barrier, the skin’s health may change and, thus, worsen diseases such as psoriasis (13).

Also, warming conditions allow some emerging infectious diseases that may trigger autoimmunity to spread more easily because of increasing insect populations, including ticks. For example, rheumatoid arthritis can be triggered by Lyme disease (15).

More research is needed to study the connection between climate change, higher temperatures, and autoimmunity.

Damiana Chiavolini, MS, PhD is a freelance writer who specializes in medical and life science topics. As a trained researcher, she authored journal articles in the areas of infection and immunity and wrote booklets and book chapters about different diseases. As a professional communicator, she writes feature articles for magazines and other publications and produces content for higher education platforms. Damiana is also an experienced academic editor, microbiology educator, writing coach, and fragrance blogger. She is a contributing member of the American Medical Writers Association and the current president of the association’s Southwest chapter.