You had a long week, and you opened that bottle of wine to help you relax — but instead you wound up with a stuffy nose you now have to deal with. It doesn't happen to everyone, but those who do get congested after a glass or two know just how much of a buzzkill it can be. So what's the deal? Why does alcohol seem to set off your allergies? And why do you have this problem, meanwhile your husband — who's drinking the exact same thing as you are — is breathing clear? As it turns out, understanding your alcohol-induced stuffy nose starts with understanding how your body processes alcohol — or tries to, anyway. From ethanol to harmless waste products — how the body metabolizes alcohol Your body holds on to the nutritive parts of what you eat and drink, but, otherwise, what goes in must also come out. And alcohol isn't exactly packed with nutrients. Through a multistep process, your body breaks down the ethanol found in your beer, wine, spiked seltzer — whatever it is you're drinking — into waste products your body can easily eliminate. The process starts with an enzyme in your liver, called alcohol dehydrogenase (ADH), which converts ethanol into acetaldehyde. Next, another enzyme called aldehyde dehydrogenase 2 (ALDH2) — and you'll want to remember this one for later — quickly breaks acetaldehyde down into acetate. What's important to note here is that the conversion of acetaldehyde into acetate needs to happen rapidly, since acetaldehyde is a pretty nasty molecule that can cause some particularly unwanted side effects (spoiler: We mentioned one in the title). Finally, acetate is further broken down into water and carbon dioxide and, voila! Your drink is on its way outside of your body. Or, that's what's supposed to happen. But, if your nose is all stuffed up or runny after just a few sips of wine, this process probably isn't proceeding as smoothly for you as it does for other people. Why some people tolerate alcohol better than others When we think about alcohol tolerance, we often think of the number of drinks a person can handle before getting giggly or slurring words. But alcohol tolerance is more complicated than just being "a lightweight" or not. In fact, alcohol intolerance is a metabolic disorder that doesn't have anything to do with how many drinks you can down before your beer goggles switch on. Alcohol intolerance is a temporary, but pretty uncomfortable, reaction to alcohol — with nasal congestion and flushed skin being the two most common side effects. It happens if your ALDH2 enzymes (remember those?) aren't particularly effective at their job, or if your body just doesn't make enough ALDH2 enzyme in the first place. In either case, the result is less acetaldehyde being broken down into acetate. And remember how I said that if acetaldehyde is allowed to build up in your body, bad things can happen? Those bad things are the side effects of alcohol intolerance, and include: Skin flushing, particularly on your chest, neck or face Stuffy or runny nose Nausea Faster than usual heart rate Lowering of your blood pressure Headache Worsening of asthma symptoms, if you suffer from asthma It all comes down to your genes Okay, so your body isn't great at processing alcohol. But as you struggle to get your "m's" and "t's" out and your husband doesn't even have an inkling of a sniffle, your next question probably becomes: Why me? (Or, maybe, why not him, too?) Having sluggish ALDH2 enzymes, or lower levels of it altogether, is ultimately the product of having genetic variation in your ALDH2 gene. Specifically, genetic changes that make your corresponding ALDH2 enzyme bad at its job. What's more is that this genetic variation can be passed down from parent to child, making alcohol intolerance an inherited condition. And since it affects your genes, once you inherit it, you're stuck with it. No ifs, ands or buts. The good news is that alcohol intolerance isn't too much of a concern. The bad news is that you can't really do much about it, or that unwelcome nasal congestion that comes along with it, aside from just not drinking alcohol. It's also important to know that there are a few other components of alcoholic beverages that can trigger side effects similar to alcohol intolerance — some of which may be more or less serious. For instance, beer and wine contain high levels of histamine, which can also contribute to a runny nose or nasal congestion. Or, maybe you're sensitive to sulfites or other chemicals in alcoholic beverages, resulting in nausea or headaches. What's more concerning, however, is that some medications can lead to uncomfortable (even dangerous) side effects when combined with alcohol. In addition, various ingredients found in alcoholic beverages have the potential to trigger an allergic reaction in some people. Sometimes it's an alcohol allergy, not alcohol intolerance That runny or stuffy nose you get if you're intolerant to alcohol may feel and seem like allergies, but it's not. An allergic reaction involves your immune response. As we now know, alcohol intolerance is an issue with metabolizing alcohol — not an overzealous immune system. However, some people do experience true allergic reactions after drinking alcoholic beverages. In this case, the ethanol isn't the culprit, but rather another ingredient in your beverage, such as a fermented grain, preservative or other chemical. Like alcohol intolerance, an alcohol allergy can cause nausea. But a person who's allergic to alcohol will likely experience more painful symptoms, such as: Stomach cramps Rash Itchiness Trouble breathing In addition, a severe reaction called anaphlyaxis can occur. Although this is rare, it can be life-threatening and require emergency care. If you have any severe or painful symptoms after drinking alcohol, don't just brush it off as alcohol intolerance. These side effects could be caused by a serious allergy and warrant a visit with your doctor to address your symptoms. Source
