What Is Anaphylaxis?


Anaphylaxis is a sudden, severe allergic reaction that can become life-threatening within minutes. It’s triggered when the immune system overreacts to a harmless substance—like food, insect venom, or medication—treating it as a dangerous invader. This response causes the release of chemicals like histamine, leading to a cascade of symptoms that affect multiple systems in the body, including the respiratory and cardiovascular systems.

Immediate treatment with epinephrine (adrenaline) is critical to stop the reaction and prevent fatal complications. Without prompt intervention, anaphylaxis can lead to loss of consciousness, respiratory arrest, or cardiac failure.

Common Causes

Anaphylaxis can result from exposure to many different allergens. The most common triggers include:

  • Food allergens such as peanuts, tree nuts, shellfish, milk, eggs, wheat, and soy

  • Medications including antibiotics like penicillin, aspirin, and NSAIDs

  • Insect stings from bees, wasps, hornets, and ants

  • Latex found in gloves, balloons, and some medical supplies

  • Exercise-induced anaphylaxis, which can be intensified by certain foods or temperature changes

Understanding your specific triggers is essential for prevention and effective management.

Symptoms to Watch For

Anaphylaxis can affect nearly every organ system and often begins within minutes of exposure. Symptoms may vary but usually follow a rapid progression through these key areas:

Respiratory Signs

  • Tightness in the chest

  • Wheezing or high-pitched breathing

  • Shortness of breath

  • Swelling in the throat or tongue

  • Hoarseness or difficulty speaking

Skin Reactions

  • Hives or welts

  • Flushed, red, or pale skin

  • Generalized itching

  • Swelling around the eyes, lips, or hands

Digestive Symptoms

  • Nausea and vomiting

  • Abdominal cramps

  • Diarrhea

Cardiovascular Issues

  • Rapid heart rate (tachycardia)

  • Weak pulse

  • Drop in blood pressure (hypotension)

  • Dizziness or fainting

Neurological Symptoms

  • Feeling of impending doom

  • Anxiety or confusion

  • Slurred speech

  • Loss of consciousness

These symptoms may escalate within minutes. Recognizing early warning signs is crucial.

Stages of Anaphylaxis

Anaphylaxis typically occurs in four distinct stages, though they may progress rapidly:

  1. Initial Reaction: Mild symptoms such as skin rash, itching, and swelling.

  2. Escalation: Symptoms spread to the lungs, stomach, and heart—trouble breathing, vomiting, and dizziness.

  3. Shock: Blood pressure drops, causing reduced blood flow to vital organs.

  4. Life-Threatening Stage: Organ failure, unconsciousness, and potentially death if untreated.

In some cases, a biphasic reaction may occur. This involves a second wave of symptoms after the initial event, sometimes appearing 1–72 hours later, even when the patient seemed to recover.

Diagnosis and Testing

Anaphylaxis is typically diagnosed based on clinical signs and patient history. Because of its rapid onset, there is often no time for tests during the reaction itself. After recovery, your healthcare provider may order tests to confirm the diagnosis and identify specific allergens.

  • Skin prick tests can identify allergens by observing skin reactions.

  • Blood tests, such as tryptase levels, help confirm that a severe allergic event took place.

Allergy specialists can then build a personalized management plan to reduce future risk.

Emergency Treatment Options

The cornerstone of anaphylaxis treatment is epinephrine—administered via an auto-injector like an EpiPen. It works by:

  • Constricting blood vessels to raise blood pressure

  • Relaxing airway muscles to ease breathing

  • Slowing the immune system’s inflammatory response

Important steps in an emergency:

  1. Administer epinephrine immediately

  2. Call emergency services (911 in the U.S. or 115 in Vietnam)

  3. Lay the person down with legs elevated unless they are vomiting or having breathing difficulty

  4. Monitor breathing and heart rate

  5. Administer a second dose of epinephrine if symptoms persist and help has not arrived

Other Supportive Treatments

Following epinephrine, medical professionals may administer:

  • Antihistamines to reduce itching and hives

  • Corticosteroids to prevent prolonged symptoms

  • IV fluids to treat shock and dehydration

  • Oxygen therapy if breathing difficulties continue

Even if the person seems better after epinephrine, they should still be evaluated in a hospital for delayed or secondary reactions.

Preventive Measures

For individuals at risk, prevention is essential. Here are key steps to minimize the chance of a future episode:

  • Avoid known allergens diligently by reading labels and asking about ingredients

  • Always carry an epinephrine auto-injector, and keep it accessible

  • Create an anaphylaxis action plan with your doctor

  • Inform others—coworkers, teachers, friends, and family—about your allergies and how to use your EpiPen

  • Wear a medical ID bracelet to alert first responders in an emergency

  • Schedule regular check-ups with your allergist or primary care provider

Complications of Untreated Anaphylaxis

Delaying treatment can lead to severe health outcomes, such as:

  • Cardiac arrest due to abnormal heart rhythms

  • Respiratory failure from swelling in the airways

  • Anaphylactic shock, leading to decreased oxygen to vital organs

  • Brain damage or death in the most severe cases

These risks highlight the importance of rapid intervention and long-term allergy management.

Living With the Risk of Anaphylaxis

Coping with a condition as serious as anaphylaxis can be emotionally challenging. Individuals often deal with fear, anxiety, and the burden of constant vigilance. To manage this:

  • Seek support groups or counseling

  • Educate yourself and those close to you

  • Keep medications up to date and stored correctly

  • Practice how to use your auto-injector

  • Don’t hesitate to ask for help if you feel overwhelmed

With the right strategies and awareness, people with anaphylaxis can live safely and confidently.