What is Anaphylaxis?

AnaphylaxisAnaphylaxis is an extreme allergic reaction that can have fatal consequences. Though it is rare , around five hundred people die due to anaphylaxis in America every year. Anaphylaxis occurs when specific substances like food or toxins from an insect bite enter the blood stream and trigger a reaction. This leads to various serious conditions like – skin breaks into hives, the respiratory rate increases, heart rate increases and the blood pressure drops rapidly. However, it is possible to control mild reactions that occur within a few seconds.

Charles Richet and Paul Portier discovered anaphylaxis about a hundred years ago. They were conducting an experiment to develop a vaccine from the toxin isolated from the Portuguese man of war using dogs. They discovered that the body first becomes sensitive to the allergen over a period and then re-exposure to the same allergen results in an adverse reaction. The dogs died within half an hour because due to anaphylaxis

Due to the serious nature of this reaction, it is necessary to learn about the causes, symptoms, and treatment of anaphylaxis.

Mechanism of anaphylaxis

The individual develops sensitivity due to exposure to the allergen, food, insect bite, or drug. This results in coating of mast cells and basophils by IgE. Re-exposure results in anaphylaxis. Anaphylactoid or non- Ig E mediated reactions occur due to direct stimulation of mast cells and basophils. Hence, the reaction can occur on the first or repeated exposures to the allergen. People with asthma are prone to anaphylaxis. The intensity varies in different individuals and faster the reaction; more serious is the nature of anaphylaxis.

Anaphylaxis signs and symptoms

Initially there is itching sensation in the arms and groin area and the skin becomes flushed. The person breaks in to hives and feels breathless. The pulse is fast; heartbeat is irregular and there is swelling in the tongue and throat. The blood pressure falls and the person may faint. The voice becomes raspy and the person cannot talk or swallow. Other symptoms include, vomiting, stomach cramps and diarrhea. Those with asthma have a blocked nose and wheezing that further hampers breathing.

Causes of anaphylaxis

As mentioned above Ig E mediated anaphylaxis is due to

  • Ingestion of foods like peanut, tree nut, fish, shellfish, soy, eggs and milk.
  • Medicines like penicillin, sulfa drugs, cephalosporins, and others.
  • Bite from insects like bees, hornet, and wasp.
  • Vaccines, latex, hormones, animal, or human proteins.

Non Ig-E mediated anaphylaxis is due to

  • Use of x-ray dyes, preservatives, some medicines like NSAIDS, aspirin and morphine.
  • Exercise or heat-induced hives can trigger anaphylaxis.

Intensity of anaphylaxis

In a mild anaphylaxis, the anaphylaxis signs and symptoms disappear within a few minutes after a person receives an emergency injection of epinephrine. This reaction will not recur upon re-exposure to the allergen. In some cases, the anaphylaxis signs and symptoms reappear after four to twelve hours and need constant monitoring. In the worst case, that affects twenty percent of the individuals, the person requires hospitalization.

Diagnosis of anaphylaxis

To determine this condition, the physician primarily asks the patient history of allergy and his/her exposure to any of the common allergens during the lifetime. Knowing about the symptoms soon after the particular allergen’s exposure is very much important. The patient should always be accompanied with any family member since the patient may be too sick to provide the entire information. The physician can diagnose the anaphylaxis only by the symptoms and the results of physical tests.

Treatment of anaphylaxis

The only treatment for anaphylactic shock is epinephrine. It helps to dilate the bronchial tubes and aids in breathing. It opens up the blood vessels and improves circulation, thus relieving stomach cramps and itching. It stops the release of mediators that can worsen the person’s condition.

Steps to overcome anaphylaxis

  • Consult a doctor to help locate the allergen. Once you are aware of the allergen causing food or medication, avoid it completely.
  • If allergic to insect bites, cover yourself fully before venturing outdoors. Taking allergy shots can help for most people.
  • Avoid exercise, latex products, and inform all medical personnel of your drug allergy before they prescribe medication for other ailments. Desensitization to the offending drug can help most patients.
  • Opt for substitutes when undergoing radiology. Pre-medication can help avoid anaphylaxis.
  • Wear a medic alert bracelet mentioning the cause of your allergy at all times.
  • Carry an Epinephrine injection to work, and with you at all times. Pre-loaded injections are now available in pre-fabricated kits for instant use. Learn to administer them and keep a kit handy at all times.

This is a complete overview of


To know about anaphylaxis caused due to physical exertion, known as exercise induced anaphylaxis, click here