7 Surprising Triggers of Anaphylaxis

In anaphylaxis, your immune system reacts to a food or substance as if it’s a harmful invader and attempts to defend your body by releasing a flood of chemicals that cause allergy symptoms. It can be scary — and life-threatening.

“Anaphylaxis is an immune response gone wild,” explains Daniel J. Stone, MD, an internist at Cedars-Sinai Medical Group in Los Angeles.

Symptoms of anaphylaxis can include shortness of breath, wheezing, tightening of the throat, hives, facial or body swelling, stomach pain, and heart palpitations, among others.

The first line of treatment for an anaphylactic reaction is epinephrine, Dr. Stone says. If you have a history of serious allergies or anaphylaxis, you should carry an epinephrine auto-injector — a pen-like device that delivers a single dose of the medication — and use it at the first sign of an episode. Then, get to the nearest emergency room right away.

Common Triggers of Anaphylaxis

“When it comes to anaphylaxis, almost anything can cause a reaction in any individual,” says Dr. Torbati. “You can eat something your entire life with no issues and then suddenly start to react to that food. And the reaction to different triggers is dynamic and develops over time. It can be unpredictable and frustrating.”

The important thing is that anaphylaxis is treatable — and being aware of your triggers can help reduce the risk of a reaction in the first place. Read on to learn more about the surprising triggers of anaphylaxis.

1. Exercise — on Its Own or With Food, Pollen, or Medication

Symptoms of exercise-induced anaphylaxis can include extreme fatigue, warmth, flushing, wheezing, itching, hives, or facial swelling during or shortly after physical activity. Anaphylaxis can also be triggered by moderate activities such as brisk walking, or vigorous yard work.

In some instances, exercise alone triggers anaphylaxis. In others, exertion combined with a food eaten just before a workout can cause anaphylaxis — and the symptoms can come on suddenly.

“A person can go jogging every day of the week and be fine,” then eat a certain food before jogging and have a reaction, says Scott H. Sicherer, MD, a pediatric allergist and immunologist at Mount Sinai Medical Center in New York City.

Other potential triggers, in combination with exercise, can be pollen or medication, such as penicillin or aspirin. To make diagnosis even more confusing, your response may not be consistent. A severe reaction may happen repeatedly or only sporadically, says Dr. Sicherer.

• Work out with a friend who can administer treatment and get help.
• Avoid exercise in extreme temperatures.
• Restrict exercise outside during allergy season.
• Avoid trigger foods before exercising.
• Take your epinephrine and seek medical help if you feel your symptoms coming on.

2. Semen

In some cases, the anaphylactic reaction occurs because the woman’s partner ate something or took a drug that she’s allergic to, which is then transferred through his semen. In other cases, it’s an allergy to seminal plasma protein, a natural component of semen.

After contact with semen, a woman may experience serious anaphylactic symptoms ranging from itching and hives to shortness of breath, throat swelling, wheezing, pelvic pain associated with uterine contractions, low blood pressure, or loss of consciousness.

3. The Menstrual Cycle

Some women experience a rare form of anaphylaxis just before or during their menstrual cycle. Known as catamenial, or cyclic, anaphylaxis, this rare disorder often goes unrecognized.

According to that study, catamenial anaphylaxis can often be controlled by a hormone called medroxyprogesterone, which regulates ovulation and menstruation. Some may find relief from symptoms after a salpingo-oophorectomy, a procedure in which the fallopian tubes and ovaries are removed. Administration of a cyclooxygenase inhibitor was also found to be effective.

If you suspect you have catamenial anaphylaxis, you should be evaluated by an allergist. Skin prick testing may be done to rule out food allergies. Your doctor’s questions may help uncover the link between anaphylaxis and your menstrual cycle.

The study also suggests that patients should complete a symptom diary, as well as a menstrual chart, to distinguish whether the anaphylactic episodes happen the week before menstruation, in the first few days of the cycle, or without any regard to the cycle.

4. Latex

If you’re a healthcare worker, hairdresser, or housekeeper who wears latex gloves, you’re at a higher risk for a latex allergy. If you have to wear latex, look for gloves that are powder-free, since they contain less latex protein — the substance that causes the allergic reaction. Wash your hands with soap and water after removing them.

If you are sensitive or allergic to latex, let healthcare workers know so you can have medical or dental procedures performed with latex-free supplies.

5. Red Meat

Meat from mammals — beef, pork, lamb, veal, venison, rabbit, and others — can cause symptoms of anaphylaxis hours after eating it, making it difficult to draw a connection between the food and allergy.

With most other allergies, “it’s unusual to have anaphylaxis hours after exposure,” Sicherer says. But with this form of anaphylaxis, you may not experience symptoms until three to six hours later, he says. That’s because it takes time to digest the meat.

6. Insect Stings

• Wear clean, light-colored clothing when outdoors. Avoid bright colors such as yellow and orange.
• Avoid perfume and scented toiletries.
• Cover up as much of your body as possible with clothing.
• Wear closed-toe shoes outdoors.
• Stay away from food and garbage when outdoors.
• Remain calm if a single stinging insect is flying around.

7. Unknown Reasons

Sometimes, anaphylaxis happens for unknown reasons.

“A person is sitting there, watching TV, and has an allergic reaction,” says Sicherer.

If you have a sudden and unexplained allergic reaction, your doctor will probably take a complete history and ask a lot of questions, such as: What did you eat or drink? Did you exercise? Did you take medication?

But sometimes, you’ll never know what triggered it. This situation baffles doctors and patients, but it’s not uncommon.

If you have a history of reactions to unknown triggers, it’s important to carry an epinephrine auto-injector with you.

“You can’t always prevent anaphylaxis,” says Torbati. But you can recognize the signs and treat it right away.

The Takeaway

• In anaphylaxis, your immune system reacts to a food or substance as if it’s a harmful invader and your body releases a flood of chemicals that cause allergy symptoms.
• While common triggers are food and insect bites, anaphylaxis can also be caused by medicine, and in rarer cases, exercise, semen, the menstrual cycle, and other triggers.
• Anaphylaxis is unpredictable, but treatable with an injection of epinephrine. If you are susceptible to anaphylaxis, you should carry an epinephrine auto-injector with you at all times. If you have a reaction, inject epinephrine and go straight to the emergency room.

Additional reporting by Nina Wasserman and Quinn Phillips.