http://www.medscape.com/viewarticle/768306?src=mp&spon=38
Major thanks to Sara Hubbell, nurse practitioner, for I suspect the most succinct summary of this emerging disease that will bring dangerous anaphylaxis to our doorsteps.
When anaphylaxis comes our way and we quickly scamper around with our medicines and 911 calls, we often try to question the alarmed patient about the "usual suspects" pine nuts, pineapple, shrimp, and the like. Note though that a new and rather novel entity, involving tick bites (mainly the Lone Star tick), anaphylaxis and red meat exposure has emerged. By red meat, this includes beef, pork, lamb, and venison. Most patients maintain a tolerance (no reation to)chicken, turkey and fish.
The presumed mechanism of action is thought to start with a Lone Star tick bite. The tick bite triggers production of IgE antibodies to the carbohydrate galactose-alpha-1,3-galactose, known thankfully as the shorter, "alpha-gal".
Sadly for the patient, the "alpha-gal" moiety is a common item in mammalian meat glycoproteins and glycolipids. As such, from the initial tick bite the patient becomes anaphylactic to red meats. As the case studies mention, the allergists can order an antibody test for IgE alpha-gal, which is usually elevated.
https://www.google.com/search?q=lone+star+tick&hl=en&prmd=imvns&tbm=isch&tbo=u&source=univ&sa=X&ei=46siUJPHNsaQ2QXepoHQCQ&ved=0CFgQsAQ&biw=1024&bih=585
Some crux urgent care points (the above link is to pictures of the Lone Star tick for all you wannabe entomologists):
- The alpha-gal anaphylaxis usually occurs 3-6 hours after eating the red meat, which is a bit delayed compared to the usual anaphylaxis reactions where the triggering event is mostly within the last 15-60 minutes.
- The alpha-gal anaphylaxis carries all the pitfalls of usual anaphylaxis, such as hypotension, syncope and hives. The treament is the same, with the mainstay being epinephrine.
- Because many allergists also will do an allergy panel to specific meats, the alpha-gal workup is best done by an allergist/immunologist. From an urgent care standpoint, it may help to remind the patient as they go to the ER to be sure to fill their epinephrine precription and consider an allergist workup. Parents also would appreciate this advice at a scary time.
Again the article is very concise. It is worth the Medscape registration if you have not done so previously, and the cases are enlightening.
The cynical side of me says this is actually a government made vector unleased on the public to combat the obesity epidemic (making red meat have the potential to kill you), but then again I know the fast food lobby is much too strong in Washington DC to have allowed that to happen.....
Comments are welcome....
Thanks for posting this Linwood! As many of you know, my husband, Brent, has had this for over 5 years now. It started with a documented tick bite in May of 2007, followed by a severe hive reaction in the middle of the night July 4 2007 that was after eating burgers for dinner. Months after "random" reactions I had a conversation with a patient who shared his story. After more research and a conversation with Dr. Scott Commons at UVA we figured out what was going on with Brent. His allergy began with beef, then pork, then lamb, then rabbit, then goat and finally venison - trying to find a meat he could eat b/c he enjoyed it. At this point we stick with fish and fowl.
ReplyDeleteThe key point that Linwood pointed out is that this happens hours after the consumption of the meat product so we need to ask questions about consumption of foods 4-6 hours prior to the episode. I would challenge us to begin bringing this up to patients with known tick bites. The latest research shows that the greater the itching reaction to the tick bite the greater the likelihood that the pt will develop the allergy. Even if this doesn't prove true, at least we can plant the thought in their heads so if they develop an allergy down the road they may remember the link.
When I gave a talk about this at the annual NP symposium in NC I had several individuals come to me and thank me for giving them a name to what they figured out over the years - many people suffer from this but have no clue as to why.
Again thanks for posting this!
Sara- thanks for the real world insight. One caveat, be careful not to make every "itchy tick bite patient" even more hysterical with a meat anaphylaxis warning. Perhaps when someone presents with the first episode of anaphylaxis (and yes, things are harried at such times,one can inquire about semi-recent itchy tick bites. As Sara points out, this may enable the patient to "connect the dots mentally" for the allergist in the future.
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