Everyone knows you can be allergic to things like peanuts, bees, and cats. For people with such allergies, they can often get through life in relative safety by simply avoiding their triggers. But some unfortunate folks have rare allergies to things that are nearly impossible to avoid, like water and sunlight. Here are a few of the weirdest triggers known to drive the immune system into an unhelpful frenzy.
A version of this story was originally published on November 5, 2020.