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Your Allergy Brain Fog Is Real

But we still aren’t really sure why

Anyone who has allergies knows how harrowing it can be to even figure out what’s causing them, let alone work through a manageable treatment that lets you live without feeling like you’re constantly walking underwater. Worse is the associated allergy condition specific to seasonal allergies: That weird, heavy-headed brain fog that makes you feel like you’re carrying around a permanent hazy mist in your head. According to The New York Times’ “Well” blog, the condition itself is real even though it can’t be measured. Though we have some ideas what’s going on, we aren’t really sure why it’s happening.

“It’s not something you could demonstrate on a test or scan,” Richard Lebowitz, a rhinologist and otolaryngologist at NYU Langone Medical Center, told them. What’s more, there are only theories as to why it’s happening. The prevailing one, the Times says: Allergies are inflammation, and inflammation elicits an immune response that produces a protein called cytokines, and it’s the cytokines fighting the infection that produces this effect—the same one you often feel with a cold, too.

This makes it sound almost cool, like allergy brain fog is just your head at war with your sinuses, but of course nothing cool ever felt so shitty that it could be described as “seeing the world through cheesecloth.” But more to the point: We seem to get the how of what happens when allergies kick in, but why don’t we get the why?

“We might have more effective treatments if scientists understood allergies, but a maddening web of causes underlies allergic reactions,” Carl Zimmer wrote at Quartz last year in a piece trying to understand the poor science of allergies. “Cells are aroused, chemicals released, signals relayed. Scientists have only partially mapped the process.”

Zimmer hung out with Ruslan Medzhitov, a researcher at the Yale School of Medicine, who’s spent decades studying immune science and has recently set out to tackle the question of why we get allergies at all. The leading theory, Zimmer notes, is that allergies are a “misfiring of defense against parasitic worms”— a leftover system for fighting infections that is no longer needed, and now amounts to an extreme overcompensation on our parts. Basically, allergens look like parasitic proteins to our immune system, so they mount the same response, but it’s way too much. But Medzhitov disagrees that this is what is really going on. Zimmer writes:

Medzhitov thinks that’s wrong. Allergies are not simply a biological blunder. Instead, they’re an essential defense against noxious chemicals–a defense that has served our ancestors for tens of millions of years and continues to do so today. It’s a controversial theory, Medzhitov acknowledges. But he’s also confident that history will prove him right. “I think the field will go around in that stage where there’s a lot of resistance to the idea,” he told me. “Until everybody says, ‘Oh yeah, it’s obvious. Of course it works that way.’

In other words, allergic reactions aren’t bad; they actually protect us. Zimmer likens to a home-alarm system for our bodies, and says they may be on the rise because we’ve gradually shifted to living indoors in “cleaner” homes filled with toxic chemicals. Other research suggests people (like the Amish) who grow up on farms, especially around dairy cows, are less prone to getting them.

That said, no one knows why some people have allergies and some people don’t, or why some people have them from birth and others develop them later, or why they can disappear altogether, Zimmer notes. But Medzhitov thinks he can prove, with mice whose antibodies are tweaked just right, that we need the shield that allergic responses provide, as miserable as they are, because otherwise toxins will damage our tissue and organs. In other words, the allergic protection system is good—we just need to know why some people’s systems overreact to the point of making them miserable.

This would be a radical shift in our understanding of allergies. It would mean, for instance, that blocking allergic responses—basically what allergy meds do—is a bad treatment, and we’d have to figure out a new one. None of this is going to make anyone with allergies or brain fog feel any better about it, but at least it means we might finally know just what the hell is going on and what to do about it.