Anaphylaxis and Epinephrine
It’s that time of year! For students with food allergies, back-to-school preparation goes beyond new clothes and school supplies. The start of the school year is a common time to review allergy action plans and refill prescriptions for epinephrine auto-injectors. Getting your prescription filled is the first step.
In EAT’s latest interview with our funded researchers, we discuss the protocol on carrying and using epinephrine with Dr. Jonathan Spergel, Chief of the Allergy Section at Children’s Hospital of Philadelphia. Dr. Spergel is a co-investigator of two EAT-funded studies: Biomarkers IgE: ‘Molecular Gene Expression During Reactions to Food: Identifying Signatures Which Correlate with Severity of Reaction’, and ‘Use of Esophageal String Test to Understand Symptoms, Inflammation and Function in Eosinophilic Esophagitis.
EAT: Let’s start with a basic question: What exactly is anaphylaxis?
Dr. Spergel: This is a great question because it’s not a simple answer. There are two general schools of thought, and it varies by physician and country. The simplest description is a reaction where you have two or more body parts reacting. Under this view, vomiting and hives, or vomiting and wheezing, is anaphylaxis. This is the generally accepted view in the United States.
In other parts of the world, anaphylaxis has to involve respiratory and cardiovascular symptoms, such as wheezing, coughing, and blood pressure drops. We have a more liberal definition in the United States because we’d rather over-treat than under-treat. There is no downside to treating an allergic reaction with epinephrine, which is a really important point.
Thankfully, fatal anaphylaxis remains rare. These deaths are almost always avoidable with proper use of epinephrine. It is worth noting that with most fatalities, hives and skin symptoms are rare. If you know you have ingested an allergen and have repeated vomiting, you should be administering epinephrine.
EAT: How does epinephrine treat anaphylaxis?
Dr. Spergel: Epinephrine is a very quick acting medicine. It helps your blood vessels constrict, so it opens airways and helps blood flow to important places. In addition, and the exact mechanism is a little unclear, epinephrine works on other receptors and basically just stops an allergic reaction. It makes hives, vomiting, and other symptoms quickly go away.
EAT: How is epinephrine different from antihistamines like diphenhydramine (aka Benadryl) or cetirizine (aka Zyrtec)?
Dr. Spergel: Epinephrine and antihistamines work in completely different ways. Antihistamines just work on histamine receptors, so they basically work on rashes and hives, and relieve a little vomiting. Epinephrine works much more globally; it helps breathing, opens airways, improves blood pressure and protects the heart.
EAT: Have the recommendations changed on when to use epinephrine versus antihistamines?
Dr. Spergel: From my perspective, as an academic allergist, the recommendation has been the same for the last 20 years. When you have a serious allergic reaction, you give epinephrine, and there has never been any doubt.
However, for community allergists and primary care providers, it has only been in recent years that they have changed their recommendation of “take diphenhydramine (aka Benadryl) and wait and see” versus what we are discussing here today. Also, in the past, emergency room physicians had more fear of potential side effects of epinephrine. Now, all of these medical professionals know it’s very safe. Cardiologists say that the side effects are minimal, especially when compared to the danger of anaphylaxis when there is cardiovascular involvement. Epinephrine can cause a racing heart, but you’ll survive that.
There has been disagreement on whether to give epinephrine for minor symptoms, or prior to the onset of symptoms. Recently, an expert panel unanimously agreed that epinephrine should not be given when there are no symptoms. However, there is still a debate on whether to give it early for minor symptoms, such as a single hive. It depends on the patient, their medical history, and access to medical care. There is not a clear answer, and this is an issue that a patient should discuss with their allergist.
EAT: For people with a food allergy, what is the recommended protocol for carrying epinephrine auto-injectors?
Dr. Spergel: Carry at least one auto-injector at all times. There is a debate on whether to carry one or two, and this depends partly on previous reaction history and distance from emergency care. The decision whether to carry one or two is something patients should discuss with their doctor. Obviously, if a person has a history of severe reactions to trace amounts, or will be far from a hospital, they should carry two.
EAT: What is the follow-up protocol for someone who has used epinephrine for an allergic reaction?
Dr. Spergel: When you use epinephrine for a severe allergic reaction, call 911 and go to an emergency room. There is some misunderstanding surrounding this recommendation. Some people think you need to go to the ER because of potential side effects from the epinephrine. That’s not it. Epinephrine is safe. You need to go to the emergency room because you are having a serious allergic reaction.
EAT: What follow-up care is provided at the emergency room?
Dr. Spergel: It varies by each individual ER. Our emergency room (at the Children’s Hospital of Philadelphia) monitors patients for 4 hours and allows patients to go home if there are no further symptoms. Some hospitals give oral steroids as a matter of course to make sure the reaction doesn’t come back, but there is debate on whether steroids help prevent a biphasic reaction. If patients have a history of biphasic reactions, they should discuss an appropriate plan with their doctor.
EAT: You were part of the research team for the recently published study, which was funded by Mylan, “Epinephrine auto-injector carriage and use practices among US children, adolescents, and adults.” What prompted this research?
Dr. Spergel: A big question in all areas of medicine is whether patients are filling their prescriptions. So many patients don’t follow their doctor’s advice on medicine, so we wanted to see how often patients are carrying and using epinephrine. This study was about understanding compliance. We really wanted to see what was going on and identify any issues that need to be addressed.
EAT: Can you give us some background on the study?
Dr. Spergel: This study was originally designed by Dr. Ruchi Gupta. It started with a survey of 172 adult patients who had been prescribed an epinephrine device, regardless of brand, for an allergy, not necessarily to food. The survey covered general questions on compliance and carriage. The next phase was to collect family surveys that applied to both children and adults. In the end, there was a sample size of 917 people.
EAT: The survey showed that while 90% of patients fill their prescriptions, only 44% carry at least one epinephrine auto injector at all times, and only 26% carry multiple injectors at all times. Can you shed some light on this discrepancy?
Dr. Spergel: My greatest concern is that only 44% carry at least one. That should be everyone, and I don’t know why they don’t. Since it’s a survey, we don’t have all the details. Maybe this group includes some people who carry epinephrine most of the time, but occasionally leave it at home when they run a quick errand, say to the library or gas station, and they know they’re not going to eat food. Unfortunately, though, I think a lot of people don’t carry at all, not even to restaurants. If you are going to a restaurant or any place where you are going to eat food, you need epinephrine with you 100% of the time.
EAT: The survey found that people are more likely to carry epinephrine if they have a supportive social environment. What does a supportive social environment look like?
Dr. Spergel: A supportive environment is pretty straightforward. It is schools, families, and workplaces that acknowledge and understand the allergic person’s medical needs, and where there is no bullying or teasing.
EAT: The survey also revealed a high percentage of respondents had not had epinephrine administered during severe reactions. Why do people hesitate to use epinephrine?
Dr. Spergel: There are many reasons: not carrying epinephrine, fear of needles, not understanding or being familiar with the signs of anaphylaxis, not wanting to go to the hospital, and a misunderstanding of the side effects of epinephrine. People think they need to go to the hospital because of the epinephrine, but the reason for going to the hospital is the allergic reaction. In 10% of anaphylaxis cases, epinephrine is not sufficient and additional medical care is needed. That is why you go to the hospital.
EAT: This may be kind of controversial, but is it better to give epinephrine even if a person is unable or unwilling to go to the hospital?
Dr. Spergel: Yes, it is better to at least give the epinephrine.
EAT: The survey found that knowledge and positive outlook on epinephrine affect people’s willingness to carry and use it. How can medical providers and the food allergy community promote increased knowledge and positivity?
Dr. Spergel: People have a more positive outlook when they understand that epinephrine is actually a very safe medication. People need to be taught that epinephrine is safe and that there are very limited side effects. There’s very little risk and there’s a lot of reward.
EAT: As you know, EAT recently launched a global Public Service Announcement (PSA): What to do when a severe food allergy reaction (anaphylaxis) strikes. EAT recommends the “Give and Go” so that people remember to GIVE epinephrine and GO call 911 when experiencing anaphylaxis. What is your perspective on the importance of using epinephrine quickly to treat an allergic reaction?
Dr. Spergel: When you have a severe reaction, it can be lifesaving. It’s that simple. There is no downside.
EAT: Dr. Spergel, thank you so much for your time today.