An Overview of Anaphylaxis

Anaphylaxis is a severe form of allergy most commonly triggered by foods, medications, and insect stings—though there are many other possible triggers. It generally has a sudden onset and is potentially life-threatening.

Anaphylaxis Symptoms

The symptoms of anaphylaxis can be significantly different from person to person. Why one person develops a particular symptom and another does not is unknown.

The two most common symptoms of anaphylaxis are hives or urticaria and angioedema.

These two symptoms occur in about 90 percent of anaphylactic reactions. The next most common symptoms are respiratory, occurring in approximately 70 percent of reactions. Respiratory symptoms such as wheezing and shortness of breath are especially common in patients with chronic lung diseases, such as asthma or COPD.

Other symptoms that commonly occur include a falling blood pressure, lightheadedness or dizziness, or passing out.

Hives are very common, with some estimates that they will affect up to 20 percent of people in their lifetime. These are raised itchy bumps that may either be red- or skin-colored. If you press down on hives they will blanch or turn white. Relieving the pressure will allow them to return to their normal color.

Angioedema is similar to hives in that both conditions involve swelling. In angioedema, the swelling, however, is under the surface of the skin and can impact other soft tissues and organs, such as your wind pipe or trachea.

Anaphylaxis impacts different parts of the body and can include symptoms specific to the organ impacted:

  • Skin - flushing, itching, hives, angioedema
  • Eyes - irritation including itching, increased tears, redness, and swelling of the skin surrounding the eyes
  • Nose - runny nose, congestion, sneezing
  • Oral - swelling of the tongue and abnormal taste
  • Lung - difficulty breathing, wheezing, chest tightness
  • Thro​at - feeling of throat swelling, hoarseness, or choking
  • Cardiac and circulatory symptoms - feeling dizzy, faint, like you’re going to pass out, low blood pressure, and a rapid or slow heartbeat
  • Nervous system - feeling of impending doom, anxiety, and confusion (i.e., You are not acting your normal self)

What Causes Anaphylaxis?

Triggers of anaphylaxis are sometimes obvious when the symptoms occur right after ingestion or contact with a particular substance. However, these are also sometimes hard to identify. Common anaphylaxis triggers include:

  • Foods - Common foods triggering anaphylaxis include peanuts, tree nuts, fish, wheat, soy, and crustaceans (e.g., shrimp). However, any food can cause anaphylaxis.
  • Medications - Antibiotics such as penicillins and cephalosporins as well as common over-the-counter pain medications and analgesics, such as aspirin and ibuprofen, are among the most common. Some people also developed anaphylaxis after immunizations or from medicines received during surgery such as anesthetics.
  • Insect stings and bites - The venom stings and bites from insects, such as bees, yellow jackets, wasps, hornets, scorpion and fire ants can all lead to anaphylaxis.
  • Latex - Rubber found in gloves, balloons, condoms, support equipment, and some medical equipment can lead to symptoms.
  • Exercise - In this rare condition anaphylaxis occurs after initiating exercise. It is more common with vigorous forms of activity, such as running, dancing, tenderness, and bicycling. However, it has also been noted to occur with less vigorous exercise, such as walking or the performance of yard work.

Anaphylaxis Risk Factors

Not everyone is at the same risk for developing anaphylaxis. If you have had a prior reaction to certain substances in the past, you are more likely to develop anaphylaxis in the future.

However, your past response to a particular substance is not predictive of future response. If you have had mild reactions in the past you could still develop more severe reactions in the future. Asthmatics and people with other chronic lung diseases are more likely to develop severe symptoms during an anaphylactic reaction.

How Does My Doctor Diagnose Anaphylaxis?

Anaphylaxis is a clinical diagnosis. Your diagnosis is based on the symptoms that occur after you’re exposed to a particular trigger such as a food, medication or medical treatment, or insect bite/sting.

After you present with symptoms that are consistent with a diagnosis of anaphylaxis, your doctor may schedule you for other testing or evaluations. These could include things such as skin testing and are discussed in more detail below.

There are also some other problems that can mimic anaphylaxis. For example, a severe asthma attack, panic attack, or heart attack may cause you to have symptoms very similar to an anaphylactic reaction. Depending on your history, physical exam, and clinical course, your doctor may want to rule out some of these conditions.

How Is Anaphylaxis Treated?

Because anaphylaxis can be life-threatening, you need to recognize the symptoms and treat it as a medical emergency. If you have an epinephrine injector, you need to use it at the first sign of symptoms, before symptoms become severe. Epinephrine is the only effective treatment for anaphylaxis. Antihistamines mainly relieve symptoms such as hives and itching, and asthma inhalers will improve respiratory symptoms, but neither will probably treat anaphylaxis.

The next very important step in treatment is to remove allergens. An allergic reaction can continue as long as the allergen is in the body. For insect stings, the key is to remove the stinger as soon as possible. The longer the stinger is in the body, the greater the reaction will be. If the allergen is topical, such as poison ivy or poison oak, you will want to wash the skin thoroughly as soon as possible. In the case of food or drug that is ingested, there is not much that you can do except to not continue taking the offending agent.

After injecting epinephrine, it is important to go to a hospital emergency department for evaluation. Here doctors and nurses can appropriately monitor you and provide further treatment as needed.

If you experience an episode of anaphylaxis it is important that you see an allergist. Allergists are medical specialists that have both experience and specialized training in the evaluation and treatment of anaphylaxis. They are the best medical professional to help you develop a plan to prevent future or recurrent episodes of anaphylaxis.

Allergists will likely order skin testing and blood tests to determine if you have true allergy and what the best treatment course for you might be.

Depending on the results of your testing and prior episodes of anaphylaxis, your allergist may recommend either antihistamines or corticosteroids as treatments for future episodes. They may also recommend immunotherapy or allergy shots to help prevent future reactions. In the case of anaphylaxis that results from an insect sting, a five-year course of immunotherapy may actually cure the allergy and significantly reduce your future risk of an episode of anaphylaxis.

How Can I Avoid Anaphylaxis Triggers?

The best way to prevent anaphylaxis is to avoid triggers once they have been identified. However, some triggers, such as certain food groups, can be difficult to avoid.

  • Food - Anytime food leads to anaphylaxis, it needs to be eliminated from the diet. You may need to learn how to read food labels and be hypervigilant about asking about the preparation and makeup of foods away from your home.
  • Insect bites/stings - Wearing protective clothing is an important factor to prevent this type of anaphylaxis. This includes wearing closed shoes, long-sleeved clothes, hats, and not drinking from open containers when outdoors.
  • Medications - You need to realize that medications have different names and are made by many different manufacturers. As a result, it is important for you to learn not only the medication that you had a specific reaction to, but also similar medications and their brand and generic names.

You should also consider wearing a medical identification bracelet. This identifies you as an anaphylactic patient, so that if you are found unresponsive, emergency responders can identify that you have suffered a potential anaphylactic reaction and they can provide you with appropriate and swift care.

A Word From Verywell

Anaphylaxis can be scary for both patients and their loved ones. Preventing and dealing with future anaphylactic reactions depends on you increasing your knowledge and acting upon it. Even though anaphylaxis can be a life-threatening condition, it is both preventable in manageable with the right treatment and support from your healthcare team.


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