Delayed anaphylactic shock is a new idea in the world of allergies. Previously, it was assumed that anaphylaxis comes on within minutes of being exposed to an allergen, or not at all.
Research carried out at University of Virginia has uncovered a severe delayed allergic reaction, which they call Delayed anaphylactic shock.
It appears to be specific to a meat allergy: beef, pork or lamb. Anaphylaxis can occur 3 to 6 hours after eating these foods for those who are allergic to it.
Symptoms can start with itching, progressing to hives on the skin’s outer and deeper layers. Swelling, intestinal irritation come next, along with airway constriction, chaotic heart beat and a rapid drop in blood pressure.
In mild cases anaphylaxis may include only the less serious symptoms, but it is possible for this to progress to the more sever, life-threatening reactions.
"Our conventional understanding is that anaphylaxis happens within seconds or minutes of exposure. The notion that it can be delayed for several hours is a paradigm altering discovery," says senior study investigator, Thomas Platts-Mills, M.D., Ph.D., Professor of Medicine and Microbiology at UVA and head of the Division of Allergy and Clinical Immunology.
The surprising thing about this allergy is that it involves a sugar, not a protein as with the allergies that science has so far become familiar with.
The reaction is triggered when IgE antibodies bind to galactose-?-1,3-galactose (alpha-gal), a kind of sugar.
So what causes the IgE antibodies to alpha-gal to be produced in the first place?
Researchers suspect it is connected with the bite of a ‘seed’ tick, the larval form of various species of ticks such as deer ticks, dog ticks etc.
The researcher suspect that seed tick bites can occasionally cause a meat allergy in people with type A or O blood. Those with B or AB blood appear to be protected from developing IgE antibodies to alpha-gal sugar.
The study also found that the most common allergy testing method used by allergists, the skin prick test, does not detect a red meat allergy.
Many allergists still believe that allergies do not develop after childhood. This study makes it clear that adults can develop a meat allergy due to larval tick bites.
When hiking in areas that may have ticks, wear clothing that protects you from tick hijacking. If you discover a tick on your skin, remove it as soon as possible in a way that removes the head of the tick from your skin.
Clothing repellents that contain permethrin (eg Permanone) can greatly reduce, but not necessarily eliminate encounters with ticks. Do not apply such repellents directly on your skin.
If you experience significant itching and redness around the bit, talk to your doctor about getting screened for an alpha-gal antibody.
{ 5 comments… read them below or add one }
sudden reaction after eating lamb
I have never eaten lamb before, and enjoyed a meal of rare lamb at my favorite Greek restaraunt tonight. It was one of the best meals I have ever eaten.
About 3 hours later, I felt suddenly dizzy and became frightened by the way I was feeling. My chest constricted, I found it difficult to breathe properly, and felt that I would pass out. My chest tightened, my heart started to race and I felt nauseous. I had to sit and felt very uncomfortable for about 10 minutes. I immediately took 2 aspirin thinking I might have had a mild heart attack. The symptoms passed.
I have never experienced these symptoms or any food allergy in my life before. Based on what I read here, I suspect an anaphylactic reaction to the lamb meat.
I had also taken blood pressure medicine (Benicar 40 HCT) shortly before consuming the meal.
Delayed Anaphylactic Shock to Chocolate, Pollen & Mold
I was stunned to see that the researchers were totally surprised that anaphylaxis can be delayed — I just take that for granted.
I have had a great number of small and large anyphylactic shock events over the last ten years (to chocolate & pollen) and they have ALWAYS been delayed. If I feel it coming, I usually have about 45 minutes to get some drugs and/or get to a safe environment.
The big delay between ingestion/exposure and the anaphylactic event is why it initially took me such a long time to figure out what was going on.
This spring I developed a new allergy and very different symptoms than I was used to — no throat constriction, face swelling or hives. Unbeknownst to me, I had suddenly developed a severe anaphylactic reaction to so-called “snow mold” (leaf mold) but it took me almost a month and a lot of visits to hospitals/doctors to sort it out.
My symptoms were: crazy heartbeat, “shocks” in my heart, constricted chest, severe angina-like pain, numb or prickling arms/fingers, sudden need to evacuate bowels, rapid drop in blood pressure, severe anxiety and feeling of doom.
Every time it happened (almost every day for over three weeks), I thought I was having a heart attack and had every test going but they all came back negative. I’m only 42 and I think all the doctors at emerg, the cardiac clinic and even my family doctor were starting to think I was a bit crazy — they were insinuating that it was just stress and I was having anxiety attacks.
A chance comment by someone else about a bad “snow mold” season this year and a “tight chest” finally let to my big eureka moment. I realized that my attacks were regularly occuring about 2-3 hours after being outside! I was so relieved to finally figure out what was going on.
I haven’t been outside for almost two weeks now (except to run to the car) and have eliminated all sorts of mold-unfriendly stuff from my diet, and I feel great!
So don’t let doctors pooh-pooh you if you think you’re having an anaphylactic attack hours later — they really do happen, and, as far as my own experience goes, they happen OFTEN!
Thanks for your Delayed Anaphylaxis story
Thanks for your story.
The medical establishment and research community tends towards a fixed idea of things.
I’m sure there are many more than a few people with similar experiences to yours. Some of them may have figured out what’s going on and some not.
The researchers were shocked because they ‘knew’ they were right about their previous ideas, only to have those ideas, that paradigm shattered.
I’m glad that you’ve worked things out.
It’s a read drag that snow mold is a new trigger. But it sounds like you are able to manage it.
Remember to put your car fan on recirculate during the snow mold season, instead of taking in outside air (in case you hadn’t thought of that).
The medical community knows very little about allergies, especially emergency room doctors who should be skilled in anaphylaxis, but they are not.
Delayed allergic reactions is the most common but the least accepted. When I had an anaphylaxis and hospitalized for a week doctors could not accept that an allergic reaction could last over three days. They were wrong.
Pollen is my nemesis. I can go outside with a mask on but the next day I pay dearly for some outside time. I am fine the day that I am out as long as I wear a face mask but the next day I have a severe cold, conjestion, stomache ache, diarrhea, and breathing issues.
I have beeen hypersensitive for over three years now since I had a drug/medicine reaction. Of course, all my life I have had sneezing and conjestion issues but it was a “cold.” Nobody ever thought to realize that I had allergies.
Your experience with doctors is unfortunately common, Julie. Some get it, many don’t, yet they still think they know more than their patients.
Given your particular experiences, I hope you leave more comments on the site to help others with challenges similar to yours.