Fatal Allergic Reactions: A Cause Identified

What triggers anaphylaxis, or life-threatening allergic reactions? You may think of peanuts, shellfish, and bee stings. But one particular substance causes more allergy-related deaths than any other allergen (allergy-causing substance), including foods and insect venom: Medications. "Drugs are the most common cause of fatal anaphylaxis," says Elina Jerschow, MD, director of the Drug Allergy Center at Montefiore Medical Center.

Anaphylaxis is a sudden, whole-body allergic response that can cause airway blockage and respiratory or cardiac arrest, any of which can result in death. Most commonly, anaphylaxis is a response to a drug, food, or insect venom allergen. (If you have seasonal allergies, take heart: allergies to pollen or trees, for example, rarely lead to anaphylaxis.)

Until recently, no one knew how many deaths in the US were due to allergic reactions to medications, because there is no central reporting agency for this particular cause of death. But in a recent study, researchers from Montefiore Medical Center and Albert Einstein College in New York, led by Jerschow, reviewed close to 2,500 death certificates filed between 1999 and 2010. They found that drug-related anaphylaxis accounted for close to 60% of all allergy-related deaths, making it the most common cause of allergy-related death in this country. In contrast, foods caused just 6.7 percent of allergy-related deaths.

Who Is at Risk?

Among the groups studied, the risk of anaphylaxis due to medication was highest among older Americans and African-Americans, next highest in whites, and lowest in Hispanic patients. The majority of deaths (more than 58%) from drug-related anaphylaxis occurred at in-patient facilities, such as nursing homes.

People with chronic inflammatory or immunity-related medical conditions are also at higher risk of developing drug allergies. (On the other hand, it’s also possible to outgrow drug allergies.)

Which Drugs Are Most Likely to Cause Anaphylaxis?

Most death certificates didn’t specify which drug caused the fatal reaction, but on the 368 certificates where the offending medication was listed, antibiotics, including penicillin and cephalosporin, accounted for about 40 percent of the deaths.

Other medications involved in anaphylactic deaths included

  • Radiocontrast agents, which are used in magnetic resonance imaging (MRIs) and computed tomographic imaging (CT scans).
  • Chemotherapy drugs used to treat cancer.
  • Sulfa drugs (sulfonamides). Sulfa drugs include some antibiotic, diuretic, thyroid, anti-inflammatory, and migraine medications.

Worryingly, there was also a significant growth in medication-related deaths over the 12-year study period. According Jerschow, this was most likely due to an increased use of medications and radiocontrast agents, as well as improved diagnostic techniques and changes in medical code reporting methods, which resulted in more drug-specific diagnoses.

But now, thanks to this study, "Medical practitioners and individuals can now be made more aware of the anaphylactic potential of certain medications, and be prepared with therapeutic and preventive strategies," Jerschow says.

How to Protect Yourself

If you’re concerned, Jerschow notes that it may be possible for a physician to identify a medication allergy. For instance, penicillin allergy can be identified by a skin prick test, and blood tests can help identify other medication allergies.

Patients should always share information about previous drug reactions with all of your health care practitioners, and be aware that drug allergies can develop over time with chronic use of some medications, including antibiotics.

Treatment Options

If you must take a certain drug to manage a particular condition, it may be possible to undergo a desensitization program, in which patients are carefully exposed to the drug in order to decrease sensitivity. Additionally, an allergic reaction to a drug can be treated with epinephrine (adrenaline) injection. When treated immediately, deadly drug-related anaphylaxis can be prevented.

Elina Jerschow, MD, reviewed this article. 


Elina Jerschow, MD. E-mail message to author. November 11, 2014.

Jerschow E, RY Lin, MM Scaperotti AP McGinn. "Fatal Anaphylaxis in the United States, 1999-2010: Temporal Patterns and Demographic Associations." Journal of Allergy and Clinical Immunology. September 30, 2014.  

"Drug Desensitization Program." Montefiore Health System. Accessed November 17, 2014. 

"Frequently Asked Questions/Drug Allergy Questions & Answers." UCLA Health/UCLA Food & Drug Allergy Care Center. Accessed November 12, 2014.