People can get heat rash waiting in lines outdoors at amusement parks or even hiking, where you've also got to look out for ticks.
"You know those amusement parks, the lines are sometimes 90 minutes long. You're out there standing for two hours in line letting everything pool. All the blood pools into your legs," said Dr. Gabe Campion, an emergency medicine physician at Dignity Health Northridge.
Ending up with a red, itchy swollen rash is pretty common.
Campion said exercise-induced vasculitis is often referred to as amusement park or golfer's rash.
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"When your body is cooling itself, your veins are expanding a little bit to help you cool off. Get more blood to the surface of your skin," he said.
Blood can pool in your legs. Campion said it can be uncomfortable, but they usually resolve after a few days.
"Things like anti-inflammatory medicines like ibuprofen, naproxen can help with it if you're able to take them safely. Cool compresses can help with them as well," he said.
You can get a heat rash while hiking. This year, the CDC said many more hikers are encountering another summer time scourge, ticks
The rate of people visiting the emergency room for tick bites is at its highest level since 2019. Scientists blame the hotter weather.
"There are more tick bites because there are more ticks. This is something where the area where ticks have lived has just expanded," Campion said.
The Northeast has had the highest rates, followed by the Midwest. Here in Southern California, doctors say Lyme disease is rare. But ticks cause other conditions, so it's important to take precautions.
"If you're walking in wooded areas and high grasses, afterwards it's important to check yourself for ticks. To prevent them in the first place, wearing long pants, long sleeves can help avoid it," Campion said.
Covering up is also a way you can avoid heat rashes. Campion said think compression socks, but that can also be difficult in the heat.
If the rash persists for more than a week or worsens, talk to your doctor. A heat rash is usually benign, but it's important to be aware of other potential causes of lower leg rashes, such as cellulitis or stasis dermatitis which may require different treatments.