Anaphylaxis

 

Anaphylaxis is a severe, life-threatening allergic reaction. It can escalate very rapidly and may require emergency medical attention to avoid fatality. Anaphylaxis is often misdiagnosed, so the true prevalence of this condition isn’t accurately known, however, an estimated 1.6-5.1% of Americans will experience an anaphylactic episode at least once in their life.

 

Symptoms of Anaphylaxis

In most cases, symptoms begin within seconds to minutes after coming into contact with a trigger (allergen), but may be delayed up to 2 hours later.

Early symptoms often look like a mild allergic reaction, such as redness, itching, and hives on the skin. But if your allergen is a food, these skin symptoms may only develop after respiratory symptoms. Other early symptoms of anaphylaxis include:

  • Coughing
  • Tightness in the chest
  • Difficulty breathing
  • The sensation of a lump in the throat
  • Stomach pain
  • Nausea and/or vomiting
  • Diarrhea
  • Swelling of the tongue or difficulty swallowing
  • Headaches
  • Sweating
  • Dizziness

If your symptoms affect more than one system of your body, this should be treated as an anaphylactic emergency. Without prompt treatment with epinephrine, anaphylaxis symptoms could progress to low blood pressure, swelling of the airway and severe difficulty breathing, a rapid and weak heartbeat, fainting, and cardiac or respiratory arrest.

 

What Causes Anaphylaxis?

Anaphylaxis is a severe hypersensitivity reaction in response to an allergen. Exposure to a trigger stimulates your immune system to release several chemicals that set off a series of physiological responses that you experience as anaphylaxis symptoms.

Common triggers for anaphylaxis include certain medications, insect venom, and foods such as:

  • Peanuts, soy, wheat, and sesame
  • Egg, shellfish, cow’s milk
  • Bee, wasp, or yellow jacket stings
  • Aspirin, ibuprofen, penicillin

Allergies to latex are also increasing in prevalence, bringing with it an increased risk of anaphylaxis from latex exposure.

People with a known history of allergies, including asthma, are at a higher risk of developing anaphylaxis.

 

Management of Anaphylaxis

People who know they suffer from anaphylaxis are typically advised to always carry an epinephrine auto-injector or nasal spray with them. At the first sign of anaphylactic reaction, even if the symptoms are still mild, you should administer epinephrine. Anaphylaxis escalates very quickly – respiratory or cardiac arrest to a medication allergy can happen within 5 minutes. If you are experiencing or witnessing an anaphylactic event and don’t have access to epinephrine, call for an ambulance immediately.

The first hour of exposure to an anaphylaxis trigger is the most crucial for treatment, as about 50% of fatalities happen within this time. But it’s important to remember that up to 20% of anaphylactic episodes have a second wave. This means that even if the first round of symptoms were successfully treated, the symptoms can return later. This biphasic reaction peaks around 8-11 hours after the first wave but can be delayed as long as 24 hours later. The second round of symptoms can be just as fatal so it’s critical to remain vigilant.

People with anaphylaxis are best managed with an allergist. An allergist can:

  • Perform controlled tests to help identify your triggers
  • Give you tips on how to avoid your triggers, including sources you may not have thought about
  • Teach you how to use an epinephrine auto-injector or nasal spray
  • Discuss whether immunotherapy may be useful
  • Help you put together an action plan for your child’s school if your child suffers from anaphylaxis

Epinephrine is the emergency treatment for someone experiencing an anaphylactic reaction. After this, additional care may be needed in hospital, such as supplemental oxygen or medications to help with inflammation and respiratory symptoms.