Extreme heat is coming. Hospital emergency physicians need to be prepared.

That’s why researchers from Northwestern University studied conditions that might come along with heat waves – and they found they’re more than just dehydration and heat stroke.

Skin conditions, multiple sclerosis and even injuries from traffic accidents could be linked to hotter weather, according to the team.

It’s hard to track heat-related illnesses. Medical records often describe the condition being treated but don’t note that heat may have contributed.

This study, in Science Advances, used a framework inspired by methods used in genomics research to examine 1,803 diagnoses recorded across nearly 1 million emergency department and urgent-care visits in Chicago between May and September 2011-2023. It identified 33 diagnoses associated with extreme heat exposure. Many were surprising or understudied.

“It is a public health obligation to protect the individuals and communities most vulnerable to the harmful effects of climate change,” says corresponding author Hyojung Jang, a Ph.D. candidate in biostatistics at Northwestern University Feinberg School of Medicine. “If we’re only tracking the more commonly known heat-related illnesses, we’ll underestimate the true heat-related health burden, which could result in vulnerable people and communities being overlooked.”

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