What Are the Signs of Anaphylaxis?

Reviewed on 1/11/2021

What Is Anaphylaxis?

Anaphylaxis signs include hives, sweating, swelling and closing off of the airways, low blood pressure, confusion and more. Anaphylaxis is a catastrophic allergic reaction and is a medical emergency.
Anaphylaxis signs include hives, sweating, swelling and closing off of the airways, low blood pressure, confusion and more. Anaphylaxis is a catastrophic allergic reaction and is a medical emergency.

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.

Many people who experience anaphylaxis have known allergies and have had previous more allergic reactions, however, even people who are unaware they have an allergy can suddenly experience severe anaphylaxis.

What Are Symptoms of Anaphylaxis?

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

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

  • Skin reactions
  • Eyes
    • Itching
    • Tearing
    • Eye redness
    • Swelling of the skin around the eyes
  • Respiratory symptoms (common in people who also have asthma or another chronic respiratory disease)
    • Difficulty getting breathing 
    • Repeated coughing
    • Chest tightness
    • Wheezing or other sounds of labored breathing
    • Increased mucus production
  • Nose, mouth, throat
    • Sneezing
    • Runny nose
    • Nasal congestion
    • Swelling of the tongue
    • Metallic taste 
    • Throat swelling or itching
    • Hoarseness
    • Change in voice
    • 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 
    • Eggs
    • Cow’s milk
    • Peanuts
    • Tree nuts
    • Fish
    • Wheat
    • Soy 
    • Crustaceans (shellfish such as shrimp) 
    • However, any food, including fruits, vegetables, seeds, spices, and food additives, can cause anaphylaxis
  • Medications
  • Venom from insects, including bees, yellow jackets, wasps, hornets, and fire ants
  • X-ray dye (radiocontrast media) given intravenously for imaging tests
  • Latex from natural rubber, found in latex gloves, balloons, some condoms, sports equipment, and medical supplies
  • Allergen immunotherapy (“allergy shots”)
  • 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

How Is Anaphylaxis Diagnosed?

Anaphylaxis is diagnosed based on symptoms that occur within minutes to an hour or so after exposure to a potential trigger.

Anaphylaxis can also resemble other health problems, such as a severe asthma attack, a heart attack, a panic attack, or food poisoning. After a patient is stabilized, additional tests may be run to rule out other conditions. 

A blood test that may be used to help confirm a diagnosis of anaphylaxis is tryptase levels, because tryptase is a natural chemical released into the blood during an anaphylactic reaction.

QUESTION

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What Is the Treatment for Anaphylaxis?

Anaphylaxis is a potentially life-threatening medical emergency. 

Use your epinephrine autoinjector, and then call 911 (or have someone call for you) to get medical treatment immediately for suspected anaphylaxis. Epinephrine is the ideal medicine used to treat anaphylactic reactions and is most effective when given promptly, before symptoms become severe. Neither antihistamines nor asthma inhalers used to treat allergy symptoms can fully treat anaphylaxis effectively, and they should not be substituted for epinephrine.

Other treatment for anaphylaxis includes: 

  • Remove known triggers 
  • Go to the hospital after using your epinephrine autoinjector for evaluation, monitoring, and possible additional treatment
    • Up to 20% of patients with anaphylaxis have biphasic (two-phase) anaphylaxis, in which symptoms resolve and then recur without further exposure to the trigger so it is important to be monitored 
    • Additional treatment in the hospital may include: 
      • Oxygen
      • Breathing tube 
      • Extra doses of epinephrine
      • Intravenous (IV) fluids and other medications 

What Are Complications of Anaphylaxis?

Complications from anaphylaxis are rare, and most patients recover completely. When complications occur, they may include: 

  • Biphasic anaphylaxis, a second reaction without the presence of the trigger
  • Low blood pressure
  • Low blood oxygen 
  • Irregular heartbeats (arrhythmias)
  • Respiratory failure from severe bronchospasm or throat swelling
  • Death, if not treated

How Do You Prevent Anaphylaxis?

Anaphylaxis may be prevented in some cases by: 

  • Consulting an allergist for information on how to prevent allergic reactions
  • Allergy testing to determine the trigger
    • Skin tests
    • Blood tests
  • Avoid known triggers
    • Eliminate known food triggers from the diet
    • Avoid locations where stinging insects are seen
    • Avoid taking medications that trigger reactions
  • Get allergy shots
  • Wear medical identification that explains your condition and known allergies to help emergency responders provide proper care

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Reviewed on 1/11/2021
References
https://www.uptodate.com/contents/anaphylaxis-symptoms-and-diagnosis-beyond-the-basics

https://www.uptodate.com/contents/anaphylaxis-treatment-and-prevention-of-recurrences-beyond-the-basics

https://www.medscape.com/answers/135065-52934/what-are-the-possible-complications-of-anaphylaxis