Anaphylaxis is a severe allergic reaction that can be fatal. By knowing your risk factors, you can take steps to reduce your chances of hospitalization.

Allergic reactions can come from all sorts of triggers, including foods, insect bites, and medications. A serious reaction can lead to life threatening complications such as anaphylaxis.

Here are some factors that increase the risk of hospitalization for severe reactions, as well as strategies for reducing the risk.

During a severe allergic reaction, symptoms get worse very quickly. Any delay in using epinephrine can increase the risk of serious effects that can lead to hospitalization. Epinephrine can reverse life threatening symptoms such as tongue and throat swelling and a sudden drop in blood pressure.

Epinephrine also reduces the release of histamine, a substance in your body that causes allergic symptoms. If you don’t use epinephrine quickly enough, the reaction can progress to anaphylactic shock.

Some research suggests that age can affect the risk of hospitalization, but the data is different for food and non-food allergic reactions.

According to a 2022 research review, people under 40 years old are more likely to have a severe reaction to a food trigger. The same review also found an association between older age and a higher risk of experiencing severe anaphylaxis symptoms in response to non-food triggers.

Being over 65 years old is a known risk factor for fatal or near-fatal anaphylaxis that requires more medical care.

Sometimes anaphylaxis symptoms will go away completely but return within 48 hours, even though you have not had another exposure to the allergic trigger. This is called a biphasic reaction or biphasic anaphylaxis.

Experts are not sure why biphasic anaphylaxis happens. But if your first reaction causes severe symptoms that take more than one dose of epinephrine to treat, there’s a greater risk that you’ll experience a biphasic reaction.

Other risk factors include skin symptoms during the reaction and wide pulse pressure (a big gap between your systolic and diastolic blood pressure).

If you go to the hospital for anaphylaxis, you might need to stay for observation in case the reaction becomes biphasic. Some treatments for severe anaphylaxis, including intravenous fluids and supplemental oxygen, can be given only by healthcare professionals and might require hospitalization.

Sometimes, inadequate management of allergies can lead to severe reactions and hospitalization.

For example, if you have allergic asthma that’s severe or unmanaged, you might have a greater risk of experiencing anaphylaxis or status asthmaticus (an emergent episode of bronchial asthma that does not respond to standard treatments).

Some health conditions can increase the risk of a severe allergic reaction or anaphylaxis, including:

  • cardiovascular disease
  • allergic rhinitis and eczema
  • severe or unmanaged asthma
  • thyroid disease
  • hereditary alpha hypertryptasemia (a genetic condition in which you have extra copies of a certain gene)
  • mastocytosis (an unusual buildup of mast cells in your body)

A recent or concurrent acute health condition, such as COVID-19, can also increase the risk.

While some medications are associated with a higher risk of severe allergic reactions, researchers are not sure whether the increase is due to the medication or the underlying condition. Medications that might increase the severity of anaphylaxis include:

  • beta-blockers
  • angiotensin converting enzyme inhibitors
  • angiotensin II receptor blockers
  • aspirin
  • nonsteroidal anti-inflammatory drugs (NSAIDs)

Additionally, the physical effects of some medications, such as sedatives and antidepressants, can make it harder for you to recognize anaphylaxis when it happens.

If you’re living with severe allergies, some strategies can help reduce your risk of hospitalization from a severe reaction, including:

  • learning about your allergic triggers and trying to avoid them
  • carrying epinephrine (such as an auto-injector pen) with you at all times
  • following your allergy management plan
  • considering treatments such as allergen-specific immunotherapy
  • having an emergency care plan and letting others know what to do in an emergency

One of the most important precautions you can take is to learn the symptoms of a serious allergic reaction. If you have symptoms in two or more areas of your body, such as your skin, mouth, stomach, or heart, you should take epinephrine or call 911 immediately.

Look for these symptoms:

  • skin itching, redness or other discoloration, or hives
  • swelling of your mouth or tongue
  • vomiting or diarrhea
  • chest pain or rapid heart rate
  • wheezing or trouble breathing
  • dizziness or a faint feeling
  • headaches
  • watery eyes
  • sweating
  • confusion

Severe allergic reactions can lead to serious complications, including anaphylaxis. Strategies such as following your allergy management plan and taking epinephrine at the first sign of anaphylaxis can help reduce your risk of hospitalization.