Photic Sneeze Reflex (ACHOO Syndrome): What Triggers It and How to Deal

If you ever start sneezing the moment you step into sunshine, you’re not alone. This odd reaction is called the photic sneeze reflex or ACHOO syndrome. It’s a harmless quirk that affects roughly 18‑35% of people, so chances are you’ve seen it in friends or family too.

Scientists think the reflex happens because the nerve pathways for bright light and sneezing overlap in the brainstem. When intense light hits your eyes, the signal can spill over to the sneeze center, causing a burst of sneezes. It’s not an allergy, it’s just a wiring shortcut that some of us inherit.

Why Some People Have It

The reflex runs in families, which means a gene is likely involved. Researchers have spotted a link to a specific region on chromosome 2, but the exact gene isn’t nailed down yet. If your parents or siblings sneeze when they step outside, you probably will too.

Age and gender don’t play a big role—kids can show the reflex just as often as adults, and men and women are equally likely to have it. The only thing that changes is exposure: people who spend more time outdoors may notice the sneezes more often.

Practical Ways to Keep Sneezing at Bay

While you can’t turn off the reflex, a few tricks can soften its impact:

• Wear sunglasses or tinted glasses. Reducing light intensity stops the trigger before it reaches your eyes.
• Gradual exposure. If you’re moving from a dark room to bright sunlight, pause at the doorway and let your eyes adjust.
• Pinch the bridge of your nose. Some people swear by a gentle press on the nasal bridge right before stepping out.
• Avoid sudden flashes. Flash photography or strobe lights can provoke sneezes, so steer clear if you know you’re sensitive.

If you need to be outdoors for long periods—like on a hike or a bike ride—keep a pair of polarized sunglasses handy and consider wearing a hat with a brim to cut down glare. Even a simple change like switching to indoor lighting that’s less harsh can help when you’re at work.

There’s no medication specifically for the photic sneeze reflex because it isn’t dangerous. If sneezing becomes disruptive, talk to your doctor about antihistamines; they sometimes dampen the response but aren’t a guaranteed fix.

Bottom line: The photic sneeze reflex is a genetic quirk that makes bright light feel like pepper for some noses. Knowing why it happens and using sunglasses or a gradual transition can make those surprise sneezes much less annoying. Embrace the fact that you’re part of an interesting minority—and keep your eyes protected when the sun shines bright.