What Are the Symptoms of Anaphylaxis?

Reviewed on 1/4/2023

What Is Anaphylaxis?

Person with anaphylaxis injecting an epipen
Symptoms of anaphylaxis include skin reactions, eye symptoms (itching, redness, tearing, skin swelling around the eyes), coughing, difficulty breathing, wheezing, chest tightness, extremely low blood pressure, rapid/slow/irregular heart rate, abdominal cramps, nausea, vomiting, anxiety, confusion, sense of impending doom, and others.

Anaphylaxis is a potentially life-threatening severe allergic reaction that comes on quickly or suddenly. Common triggers for anaphylaxis include foods, medications, and insect stings. When a trigger cannot be identified, it is called idiopathic anaphylaxis.

Anaphylaxis is a medical emergency. Use your epinephrine autoinjector and then call 911 (or have someone call for you) to get medical treatment immediately for suspected anaphylaxis.

Anaphylaxis may occur in people with known allergies who have had previous allergic reactions, but even those who are unaware they have an allergy can suddenly experience severe anaphylaxis. 

Symptoms of anaphylaxis usually begin within minutes to an hour after exposure to a trigger and include: 

  • Skin reactions
  • Eyes
    • Itching
    • Eye redness
    • Tearing
    • Skin swelling around the eyes
  • Respiratory symptoms (common in people who also have asthma or another chronic respiratory disease)
    • Coughing
    • Difficulty breathing 
    • Wheezing or other sounds of labored breathing
    • Chest tightness
    • Increased mucus production
  • Nose, mouth, throat
    • Runny or stuffy nose
    • Sneezing
    • Tongue swelling
    • Metallic taste in mouth
    • Hoarseness
    • Change in voice
    • Throat swelling or itching
    • Sensation of choking
  • Extremely low blood pressure 
  • Heart
    • Weakness
    • Rapid, slow, or irregular heart rate
  • Digestive system
  • Nervous system
    • Anxiety
    • Confusion
    • Sense of impending doom

What Causes Anaphylaxis?

Anaphylaxis is caused by a severe allergic reaction to triggers such as foods, medications, and insect stings. 

Common anaphylaxis triggers include:

  • Foods 
    • Any food can cause anaphylaxis, though some of the more common triggers include: 
      • Peanuts
      • Eggs
      • Crustaceans (shellfish such as shrimp) 
      • Cow’s milk
      • Tree nuts
      • Fish
      • Wheat
      • Soy 
  • Medications
  • Venom from insects, including bees, yellow jackets, wasps, hornets, and fire ants
  • Latex from natural rubber, found in latex gloves, balloons, some condoms, sports equipment, and medical supplies
  • Exercise, either alone or after ingesting food or medication
  • Less common triggers include: 
    • Human seminal fluid (semen)
    • Cold water or cold air

Risk factors for developing anaphylaxis include: 

  • Previous severe anaphylactic reactions 
  • Asthma and other chronic lung diseases 
  • Other diseases, such as cardiovascular disease and coronary artery disease

What Is the Treatment for Anaphylaxis?

Anaphylaxis is a potentially life-threatening medical emergency. If you suspect anaphylaxis is occurring, use your epinephrine autoinjector, and then call 911 (or have someone call for you) to get medical treatment immediately. 

Epinephrine is the ideal medicine used to treat anaphylactic reactions and is most effective when given promptly, before symptoms become severe. Antihistamines and asthma inhalers used to treat allergy symptoms will not fully treat anaphylaxis effectively, and they should not be used instead of epinephrine.

Other treatment for anaphylaxis includes: 

  • Remove known triggers 
  • Go to the hospital after using an epinephrine autoinjector 
    • Evaluation, monitoring, and additional treatment may be needed
    • Up to 20% of patients with anaphylaxis have biphasic (two-phase) anaphylaxis, in which symptoms resolve and then occur again without further exposure to the trigger so it is important to be monitored 
    • Additional treatment in the hospital may include: 
      • Extra doses of epinephrine
      • Intravenous (IV) fluids and other medications 
      • Oxygen
      • Breathing tube
Reviewed on 1/4/2023
Image source: iStock Images