Allergies are tricky. Sneezing, coughing, and an upset stomach are just a few of the common allergic reaction symptoms that an estimated 50 million of us deal with at any time during the year, according to the American College of Allergy, Asthma & Immunology (ACAAI). But they’re easy to mistake for other issues like a bad cold, the flu, COVID-19, or a food intolerance. And if it’s been a while since you last saw a doctor or you don’t have the time for an appointment, you may have just learned to live with the symptoms.
Although allergies often first arise in childhood, they could emerge at any time, the ACAAI notes. Symptoms can range from mild annoyances (typically spurred via environmental allergens like pollen or mold) to a severe and life-threatening medical emergency (typically spurred via food allergies, the most common trigger of anaphylaxis). That’s why it’s worth paying attention to the signs of an allergic reaction.
Left untreated, allergies can also lead to worsening symptoms of related conditions like allergic asthma or chronic sinus infections. They could also disrupt your sleep and in turn your mood, energy levels, and overall health.
There’s no need to suffer endlessly, though. Coping tools and treatment can help you get your symptoms under control. Learn everything you need to know about allergic reaction symptoms, the causes, and how you can prevent them.
“An allergic reaction is when your immune system becomes hypersensitive to something,” Purvi Parikh, MD, an allergist and immunologist with the Allergy & Asthma Network, tells SELF. Your immune system helps defend your body against potentially dangerous intruders like bacteria and viruses. But sometimes it mistakes certain harmless substances as threats. These are known as allergens.
As a result, your immune system creates Immunoglobulin E (IgE) antibodies, which are special proteins in the blood that activate to “protect you” from these “enemies,” Amina Abdeldaim, MD, a board-certified allergist in New York City, tells SELF. They dock on a special allergy cell called a mast cell, which then releases chemicals that cause the allergic reaction, including histamines and other proteins, Dr. Abdeldaim says. As they flow through your bloodstream, your blood vessels expand, causing swelling and irritation in the affected area.
It’s this chain of events that’s responsible for the distressing allergy symptoms that follow. Allergic reactions can arise after you inhale, eat, drink, or touch something you’ve developed a sensitivity to.
Allergic reactions don’t always happen the first time you’re exposed to a potential allergen. For example, initially, a bee sting may only cause a little red bump and mild discomfort at the sting site. But after your body has logged bee venom as a dangerous substance, your next bee sting could cause a more severe reaction like hives or trouble breathing.
“An allergic reaction occurs when your body’s immune system is dysregulated,” Schuman Tam, MD, a double board-certified allergist and immunologist at MarinHealth Medical Center in Greenbrae, California, tells SELF. But what exactly is at the root of this dysregulation isn’t entirely clear.
Scientists also aren’t sure why certain substances cause allergies and others don’t, per the American Academy of Allergy, Asthma, & Immunology. What is known is that the biggest risk factor for having an allergic reaction is having a family history of allergies.
Common allergens include foods like cow’s milk; hen’s eggs; peanuts; tree nuts; wheat; soy; fish or shellfish; pollen and mold; pet dander; dust mites; insect venom from bees, wasps, hornets, and ants; latex; and medications such as antibiotics, aspirin, and non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen.
