Anaphylaxis symptoms might subside after epinephrine treatment, but they could return, even hours later. Always go to the ER after an anaphylactic reaction in case you need follow-up care.

There are few things more frightening than having or witnessing an anaphylactic reaction. The symptoms, which can go from bad to worse very quickly, may include:

  • trouble breathing
  • hives
  • facial swelling
  • vomiting
  • fast heartbeat
  • fainting

If you see someone experiencing symptoms of anaphylaxis or if you have symptoms yourself, call emergency services immediately.

If you’ve had a severe allergic reaction in the past, your doctor might have prescribed emergency epinephrine, which comes in a device called an auto-injector. If you experience anaphylaxis, getting an injection of epinephrine as quickly as possible can save your life. But what happens after you use epinephrine?

Ideally, your symptoms will begin to improve. Sometimes, they might even resolve completely. As a result, you might assume that you’re no longer in any danger, but that’s not the case.

A trip to the emergency room (ER) is still required, no matter how well you feel after an anaphylactic reaction.

Usually, epinephrine can quickly relieve the most dangerous symptoms of anaphylaxis, including throat swelling, trouble breathing, and low blood pressure.

Epinephrine is the treatment of choice for anyone experiencing anaphylaxis. However, for this medication to be the most effective, you need to use it within the first few minutes after the allergic reaction starts.

Remember that you should only give epinephrine to a person who has been prescribed the medication. You should also follow the instructions carefully. Dosages vary, and individual medical conditions can affect how a person reacts to the medication.

For example, because epinephrine speeds up the heart rate and increases blood pressure, it could cause a heart attack in someone who has heart disease.

Give an epinephrine injection only if someone has been exposed to an allergy trigger and is experiencing any of the following symptoms:

  • trouble breathing
  • swelling or tightness in their throat
  • dizziness

Give an injection to a child who has been exposed to an allergy trigger and is experiencing any of the following:

  • loss of consciousness
  • vomiting multiple times after eating a food they’re severely allergic to
  • coughing and difficulty catching their breath
  • swelling in their face and lips

Before using an epinephrine auto-injector, read the instructions. Each device is a bit different.

Important

When you receive your epinephrine auto-injector from the pharmacy, BEFORE you need to use it, examine it for any deformities. Specifically, look at the carrying case and make sure it’s not warped and that the auto-injector will slide out easily. Also, examine the safety cap (usually blue) and be sure it’s not raised. It should be flush with the sides of the auto-injector. If any auto-injector does not slide out of the case easily or if it has a safety cap that is slightly raised, take it back to the pharmacy for a replacement. These deformities can cause a delay in administering the medication, and any delay in treating an anaphylactic reaction can be life threatening. Again, BEFORE you need to use it, examine the auto-injector and make sure there are no deformities.

In general, to give an epinephrine injection, follow the steps below:

  1. Slide the auto-injector out of the carrying case.
  2. Remove the safety cap, which is usually blue. To do this properly, hold the body of the auto-injector in your dominant hand and use your other hand to pull the safety cap straight up and off. DO NOT try to hold the auto-injector in one hand and flip the cap off with the thumb of the same hand.
  3. Hold the auto-injector in your fist, with the orange tip pointing down and your arm at your side.
  4. Swing your arm out to your side (as if you’re making a snow angel) and then quickly down to your side so that the tip of the auto-injector goes directly into the side of your thigh with some force.
  5. Keep it there, pressing down and holding for 3 seconds.
  6. Remove the auto-injector from your thigh.
  7. Place the auto-injector back in its case.

After you inject the medication, call 911 or your local emergency services if you haven’t already done so. Tell the dispatcher about the anaphylactic reaction. Alternatively, if you live close to a hospital and can get there quickly, go immediately to the ER for medical attention and disposal of your auto-injector.

While you wait for medical help to arrive, take these steps to keep yourself or the person who’s having the reaction safe:

  1. Remove the source of the allergen. For example, if a bee sting caused the reaction, remove the stinger by using your fingernails or scraping the edge of a credit card over it until it comes out. Do not use tweezers, which can squeeze more venom out of the stinger.
  2. If the person is fainting or feels like they’re about to faint, help them lie down flat on their back and raise their legs so that blood can get to their brain. You can cover them with a blanket to keep them warm.
  3. If they’re vomiting or having trouble breathing, especially if they are pregnant, sit them up and a little forward if possible, or lay them on their side.
  4. If the person loses consciousness, lay them down with their head tilted back so that their airway is open and check for a pulse. If there is no pulse and the person is not breathing, give two quick breaths and start CPR chest compressions.
  5. Give other medications, such as an antihistamine or an inhaler, if they’re wheezing.
  6. If the person’s symptoms don’t improve, give them another injection of epinephrine, if it’s available. Doses should occur 5 to 15 minutes apart.

An injection of emergency epinephrine could save a person’s life after an anaphylactic reaction. However, the injection is only one part of the treatment.

Everyone who has had an anaphylactic reaction needs to be examined and monitored in the ER, because anaphylaxis is not always a single reaction. The symptoms can return hours or even days after the first epinephrine injection.

Most cases of anaphylaxis occur quickly and resolve completely after they’re treated. However, the symptoms might subside and then start again a few hours later, and sometimes, they do not subside for hours or days.

An anaphylactic reaction can occur in three possible patterns:

  • Uniphasic reaction: This is the most common type of reaction. Symptoms peak within 30 to 60 minutes after you’re exposed to the allergen. The symptoms subside within an hour, with or without treatment, and they don’t return.
  • Biphasic reaction: In a biphasic reaction, symptoms go away for an hour or more but then return without another exposure to the allergen. The second reaction can happen within 72 hours of the first.
  • Protracted anaphylaxis: This type of anaphylaxis is relatively rare. The reaction can last for days or even weeks without fully resolving.

Someone who has had an anaphylactic reaction may need to be monitored in an ER for 4 to 12 hours afterward, depending on certain factors.

If the person does not already have a prescription for an epinephrine auto-injector, they will receive one, along with an action plan for how and when to use the medication in case of a recurrence.

Because of the risk of a rebound anaphylactic reaction, proper medical evaluation and aftercare are crucial, even if you feel fine after epinephrine treatment.

When you go to the ER for anaphylaxis treatment, healthcare professionals will do a full examination. They will check your breathing and give you oxygen if needed.

If you continue to wheeze and have trouble breathing, you may be given other medications by mouth, intravenously (directly into a vein), or with an inhaler to help you breathe more easily.

These medications might include:

You’ll also receive more epinephrine if you need it. Healthcare professionals will carefully observe you and give you immediate medical attention if your symptoms come back or worsen.

If you experience an especially severe reaction, you may need a breathing tube or surgery to open your airway. If your reaction does not respond to epinephrine injections, you might need to receive the drug intravenously.

Once you’ve been successfully treated for an anaphylactic reaction, your goal should be to avoid another one. The best way to do that is to stay away from your allergy trigger.

If you’re unsure what caused your reaction, see an allergist for a skin prick test or blood test to identify your trigger.

If you’re allergic to a certain food or ingredient, read product labels to make sure you don’t eat anything that contains it. When you eat out, let the server know about your allergies.

If you’re allergic to insects, wear an insect repellent whenever you go outdoors in the summer and stay well covered with long sleeves and long pants. Consider lightweight clothing options for the outdoors that keep you covered but cool.

Never swat at bees, wasps, or hornets — this may cause them to sting you. Instead, slowly move away from them.

If you’re allergic to any medication, tell every doctor you visit that you have an allergy so that they don’t prescribe that drug for you. Also, let your pharmacist know. Consider wearing a medical alert bracelet to let emergency responders know that you have a drug allergy.

Always carry an epinephrine auto-injector with you in case you encounter your allergy trigger in the future. If you haven’t used it in a while, check the date to make sure it hasn’t expired.

It’s important to go to the ER after an anaphylactic reaction, even if you’ve used epinephrine and your symptoms have subsided. Healthcare professionals may want to monitor you in case you experience another reaction.

If you have severe allergies that may lead to anaphylaxis, keep an epinephrine auto-injector with you at all times. Additionally, ensure that anyone you spend a lot of time with knows how to use it in case of an emergency.