Many people living with systemic mastocytosis (SM) are sensitive to heat — but the risk doesn’t end when cool autumn breezes finally arrive. From a hot bath to a stuffy sweater, heat intolerance can appear in many parts of daily life year-round. Here are some techniques to avoid triggering a symptom flare-up.
Why does mastocytosis cause heat intolerance?
Heat affects the body by activating the body’s inflammatory response, leading to symptoms.
Blood vessels dilate as a result of higher temperatures. As mast cells are located around blood vessels, this dilation causes mast cell activity. In SM, this involves mast cells releasing excessive amounts of a symptom-triggering mix of chemicals including cytokines, leukotrienes and histamines.
Sweat poses an additional problem. Sweating from overheating can alter pH levels in the skin, which irritates mast cells. The friction from clothes rubbing on hot, sweaty skin can also trigger mast cell activity.
While heat intolerance is more common, some people with SM are also triggered by cold, or by sudden shifts in temperature.
What are the symptoms of heat intolerance in SM?
The most common symptoms provoked by heat and humidity are skin related. They may include skin irritation, flushing, hives and itching. Heat intolerance may also cause fatigue, fainting, dizziness, breathlessness, nausea and even anaphylaxis.
Read more about SM FAQs
Tips for managing temperature shifts
Being sensitive to heat and sudden temperature shifts can be a challenge, but there are steps you can take to live better with systemic mastocytosis:
Managing heat in warmer months
- Protect yourself from the sun with a wide-brimmed hat and long sleeves.
- Plan your day around the temperature: As much as possible, save your time outdoors for the morning or evening hours.
- Don’t exercise when it is hot. Or choose to exercise indoors, with good air conditioning.
- Wear cooling headwear that doesn’t trap sweat, or throw a cooling towel or cold washcloth around your neck.
- Keep a misting bottle in the fridge for a quick cooling spritz.
- Personal fans are also a good option to help keep your temperature regulated.
- Stay hydrated throughout the day, and carry water with you.
Navigating heat intolerance in colder months
- In the winter months, take off your hat and gloves if you start to overheat; some patients find this helps them cool down more quickly than simply unzipping their jacket.
- Wear layers to help you adjust to the temperature. The thick sweater that’s cozy at home might be much too hot at work.
Avoiding sudden temperature shifts year-round
- Hot water is a common trigger. Regulate the water temperature before showering or washing your hands to avoid sudden high temperatures. Avoid hot and humid environments, such as saunas and steam baths.
- Be cautious of cool pools, unless you know the cold won’t trigger your symptoms.
- Consider getting a remote start for your car, so it can cool down in the summer before you get inside — or warm up in the winter without blasting you with hot air.
- If your house is already warm, standing by the stove to cook dinner (or even having the oven on) can warm you up even more; try a stove-free meal during the summer and temporarily turning the thermostat down during the winter.
Carry antihistamines with you in case you feel discomfort due to heat and humidity and the onset of associated symptoms. Keep two doses of epinephrine with you too, in case of anaphylaxis. Living with the symptom burden of SM can seem overwhelming at times, but once you familiarize yourself with your triggers and how to avoid them, you will manage your symptoms more effectively.
Sign up here to get the latest news, perspectives, and information about SM sent directly to your inbox. Registration is free and only takes a minute.
