There are few things more frightening than having or witnessing an anaphylactic reaction. The symptoms can go from bad to worse very quickly. Getting a shot of emergency epinephrine as quickly as possible can save a person’s life—but what happens after the epinephrine? Ideally, a person’s symptoms will begin to improve, and in some cases they can even resolve completely. This may lead the person who had the reaction to believe that they are out of the woods and no longer in any danger. Unfortunately, this is not the case. A trip to the emergency room is still required, no matter how well the person may feel following their anaphylactic reaction.

Risk of Rebound Anaphylaxis after Emergency Epinephrine

An injection of emergency epinephrine could save your life following an anaphylactic reaction to an allergen. However, the injection is merely part of the treatment that you may require. All patients who have undergone anaphylaxis need to be examined and monitored. This is because anaphylaxis is not always a single reaction. The symptoms can rebound, returning hours or even days after the autoinjector of epinephrine has been administered.

According to the National Institute of Allergy and Infectious Diseases, an anaphylactic reaction can be a single occurrence with symptoms that resolve within minutes, with or without treatment. Alternately, it can be a single but long-lasting reaction that can continue for hours or even days. Anaphylaxis can also occur as two reactions, in which the symptoms seem to resolve but then reappear. With this two-part type of reaction, the symptoms most commonly return approximately eight hours after the first reaction. However, symptoms can return as many as 72 hours later. According to a paper published in 2010 in Canadian Family Physician, patients with severe anaphylactic reactions, especially those whose symptoms come on rapidly, have up to a 20 percent risk of a rebound in symptoms. The study’s researchers recommended that even people who experience a single occurrence that resolves quickly and completely be monitored in the emergency department for up to eight hours after the reaction. They also advise that these patients be sent home with a dose of emergency epinephrine due to the possibility of reoccurrence.

Anaphylaxis Aftercare

The risk of a rebound anaphylactic reaction makes proper medical evaluation and aftercare crucial, even for those who may feel fine following treatment with epinephrine.

Once an anaphylaxis patient enters the emergency department, the doctor performs a full examination and ensures that the airway is stable. Supplemental oxygen is provided. In cases where wheezing and labored breathing continues, you may be given other medications orally, through an IV, or via an inhaler. More epinephrine will be provided throughout your stay. Continuous observation ensures that you will get immediate attention if your symptoms worsen or return. In particularly extreme cases, a breathing tube may be inserted into the trachea, or surgery may be performed to open the airway.

If an anaphylaxis patient has low blood pressure, also known as hypotension, epinephrine might be provided intravenously. There is a risk, however, that a patient will experience heart issues when receiving epinephrine in this way. For this reason, cardiac monitoring is required in case of arrhythmia, which is an abnormal change in your heart’s electrical impulses, or ischemia, which is a restriction in blood flow and oxygen to the heart.

The risks associated with anaphylaxis, even after emergency epinephrine treatment, make a trip to the emergency room for a medical examination well worth it no matter how you feel.