Death from anaphylaxis extremely rare and unfortunate, despite recent cases

Fatal occurrences of the severe allergic reaction are generally triggered by medications, blood transfusions or insect stings

Anaphylaxis: Symptoms can recur after treatment with epinephrine, which makes it important to seek hospital treatment after a severe allergic reaction. Photograph: Jeff Moore/PA Wire
Anaphylaxis: Symptoms can recur after treatment with epinephrine, which makes it important to seek hospital treatment after a severe allergic reaction. Photograph: Jeff Moore/PA Wire

The death of 56-year-old father of three, Michael Sheehan from Co Cork, after suffering what is believed to be an allergic reaction to wasp stings, is a rare event.

While a definitive cause of death must await the results of a postmortem examination, friends have confirmed he was stung on the back and the neck several times while hedge cutting at his home in Macroom. They have described him experiencing symptoms highly suggestive of anaphylactic shock, a short time after being stung.

Anaphylaxis is a severe, life-threatening allergic reaction and is most often triggered by the ingestion of a specific food or medication. It can happen seconds or minutes after a person has been exposed to something they are allergic to.

In anaphylaxis, the immune system releases a flood of chemicals that can cause the body to go into shock. Airways constrict and blood pressure drops precipitately. Symptoms can occur immediately after exposure to the allergen and worsen rapidly.

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Michael Sheehan was cutting a hedge when he was stung on the back and neck. Photograph: rip.ie
Michael Sheehan was cutting a hedge when he was stung on the back and neck. Photograph: rip.ie

Deaths due to anaphylaxis are very rare; they are estimated to occur in about one in two million people per year. Fatal anaphylaxis is more commonly triggered by medications, blood transfusions or insect stings rather than an allergy to a specific food.

However, in a separate fatality, Co Kilkenny woman Aika Doheny died two years ago following what is believed to have been an allergic reaction to a soya-based coffee drink. It has been reported that she died despite receiving an injection of epinephrine in the form of an EpiPen shortly after she became unwell while on holiday in Japan.

Epinephrine (a form of adrenaline) is a self-injectable medication and is the first-line treatment for severe or life-threatening allergic reactions. An EpiPen is usually administered through a muscle in the outer thigh area. Epinephrine is a highly effective medication but it must be given promptly during anaphylaxis to be most effective.

An allergic reaction may sometimes improve after treatment with epinephrine, but symptoms can recur. This makes it important to seek hospital treatment after an anaphylactic event. Adults will usually be observed in hospital for up to 12 hours, while children require an overnight admission.

What are the symptoms of anaphylaxis?

  • Rash, hives or swelling
  • Difficulty breathing
  • Lightheadedness, faintness or confusion
  • Nausea, vomiting or abdominal pain
  • Collapse

Doctors make a diagnosis of anaphylaxis based on the following criteria: the sudden onset of symptoms with rapid progression; the presence of a rash, hives or swelling in the face or throat; and life-threatening breathing or circulation problems.

Death from anaphylaxis, despite the two recent cases in otherwise healthy people, is extremely rare and unfortunate.