Anaphylactic Shock: What You Should Know

Written by Hope Cristol
Medically Reviewed by Melinda Ratini, MS, DO on April 02, 2025
5 min read
Act Fast -- Why Every Second CountsIf you have a life-threatening allergic reaction, it’s important to react fast. Every second counts.79

THOMAS CHACKO: The number one

thing that you need to know

if you're having

a life-threatening

anaphylactic-like reaction

is to make sure you have

epinephrine at hand.



That is the one life-saving

emergency treatment.

So that you should make sure you

have available

and be

aware and available and able

to use.



Speed of which you get

the medicine in is probably

priority number one.



The reason why is because you

could have a food

allergic reaction

and the fatalities

occur within minutes.

So you really need to get

the medicine in you

within minutes if it's going

to be a bad one.



So that's why speed is quick.

These anaphylatic reactions,

the bad ones,

happen within minutes,

especially insect stings.

Minutes, not 30 minutes, not

hours, it can occur within five,

10 minutes, or shorter.



Epinephrine works very quickly.

It works within minutes.

You could see the reaction work

within less than five minutes,

maybe even earlier than that.

So that's why epinephrine is

the drug of choice

because it reverses things very

quickly.



Let's say you have been

an anaphylactic reaction

and you don't have treatment,

it can be just hives.

It could be swelling

or angiodema, swelling

of your lips or your tongue.



But it could be as bad as I'm

passing out hypotension, not

enough blood or oxygen

to the brain.

And then, it could be

the fatality or death.

And that's what we're-- those

are the ones that we're really

scared about.

<p>Thomas Chacko, MD Allergist</p>/delivery/c6/40/c640fb48-4e4b-4b14-b3c2-074712cf8e9c/vd-1068-remember-during-severe-allergic-reaction_,2500k,400k,4500k,750k,1000k,.mp412/17/2015 07:00:00 PM650350thomas chacko, md/webmd/consumer_assets/site_images/article_thumbnails/video/vd_1068_remember_during_severe_allergic_reaction_video/650x350_vd_1068_remember_during_severe_allergic_reaction_video.jpg091e9c5e8131c701

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 dose of a drug called epinephrine (adrenaline) is needed immediately. If it doesn't stop your symptoms quickly and completely, you'll need to 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.

You need a dose of epinephrine, either as a shot in your thigh or in a nasal spray,  right away. You may not need emergency medical care afterward if you recover quickly and fully and have more epinephrine on hand. But call 911 if:

  • Your reaction is severe
  • Symptoms don't get better quickly and completely or nearly completely
  • Symptoms come back or get worse

You could be 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 may also get fluids 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 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 use it
  • When to call 911