Anaphylactic Shock: What You Should Know

Medically Reviewed by Carol DerSarkissian, MD on November 19, 2022
3 min read

Anaphylactic shock is a rare but severe allergic reaction that can be deadly if you don't treat it right away. It's most often caused by an allergy to food, insect bites, or certain medications.

A shot of a drug called epinephrine is needed immediately, and you should call 911 for emergency medical help.

The terms "anaphylaxis" and "anaphylactic shock" are often used to mean the same thing. They both refer to a severe allergic reaction. Shock is when your blood pressure drops so low that your cells (and organs) don't get enough oxygen. Anaphylactic shock is shock that's caused by anaphylaxis.

You typically notice the first symptoms within 15 minutes of coming into contact with the thing you're allergic to. They may start out mild, like a runny nose or an uneasy feeling. But they can get much worse very fast. Some typical symptoms include:

In severe cases, people collapse, stop breathing, and lose consciousness in just a couple of minutes.

A shot of epinephrine in your thigh is needed right away, and you should call 911 because you're at risk for a second reaction (called a biphasic reaction) within 12 hours. At the emergency room, doctors can keep an eye on your symptoms and treat you in case of a second reaction.

If you don't have epinephrine, emergency room doctors can save your life. They'll put a shot of epinephrine under your skin or in a muscle or vein. Usually this gets your blood pressure, which drops during anaphylactic shock, back to normal. You'll also get fluids, steroids, and antihistamines (drugs used to treat allergic reactions) through a tube connected to one of your veins until your symptoms are gone.

Other possible treatments include a breathing tube and medications to help you breathe better, and a corticosteroid (a powerful anti-inflammatory drug) to keep symptoms from coming back hours later.

The most common causes of an anaphylactic reaction include:

  • Foods, especially nuts and shellfish
  • Latex, found in many disposable gloves, syringes, and adhesive tapes
  • Medications, including penicillin and aspirin
  • Insect stings

Usually, you have to come into contact with a trigger more than once before you have a severe allergy to it. So tell your doctor if you were stung by a bee and that spot swelled up or if your throat felt scratchy the one time you ate shrimp. They may want you to keep medicine on hand in case a severe reaction happens next time.

Even a mild allergic reaction can lead to more serious ones in the future. Talk to your allergist or primary care doctor about whether you should keep a shot of epinephrine handy at all times.

The best prevention is to avoid your triggers. Since you may not be able to do that all the time, make sure you have a plan to spot and treat symptoms of anaphylaxis right away. Your primary care doctor or allergist can help you with this.

It's a good idea to wear a medical alert bracelet to let people know about your allergy in case you're not able to talk. You also should tell your friends and family so they can help you in an emergency. Be sure they know:

  • Your allergy trigger(s)
  • Signs of an anaphylactic reaction
  • Where you keep epinephrine and how to give you a shot
  • When to call 911