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Ever heard of a tick meat allergy (also known more formally as alpha-gal syndrome)? This is caused by the bite of a very specific type of tick which then triggers an allergy to mammalian meat (that comes from cows, pigs, sheep, etc.).
Alpha-gal syndrome is different to other food allergies. Take peanut allergies, for example. Symptoms like hives and wheezing typically show up very quickly after consuming peanuts or peanut-containing foods.
If you have an alpha-gal allergy, it usually takes a few hours between meat consumption and the onset of symptoms. This can make it very tricky to diagnose.
Because an alpha meat allergy is not just to one type of animal, it causes a significant diet change AND is tricky when it comes to picking supplements (as this type of allergy isn’t on the top 9 allergen list).
Joining me to shed some light on alpha gal mammalian meat allergy is Dr. David Fitzhugh, an allergist/immunologist in private practice in Chapel Hill, North Carolina.
He specializes in food immunotherapy for children and adults with severe food allergies but treats a wide variety of allergic and immunologic conditions, including allergic rhinitis, asthma, atopic dermatitis, mast cell disorders, and anaphylaxis.
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In This Episode:
- What is alpha-gal syndrome and what triggers it?
- Tick meat allergy origins
- Who is at risk for alpha-gal allergy?
- How is alpha-gal syndrome diagnosed?
- Alpha-gal allergy symptoms
- What is pork-cat syndrome?
- Timeline from tick bite to triggering alpha-gal allergy symptoms
- Alpha-gal syndrome and dairy: Is it problem?
- Medications to avoid if you have alpha-gal syndrome
- Is there treatment available for alpha meat allergy?
Quotes
“You have to live where the tick is prevalent, number one. And number two, you know the typical person that we might see with alpha-gal tends to be someone who spends a lot of time outdoors because those are people that are getting tick bites…And again I'll reinforce, of course, not everybody who gets bit by Lone Star Tick develops alpha-gal.”
“Patients, in my experience, they have this sort of palmar-plantar itching, right? They complain of itching on the palms of their hands, soles of their feet, and then sometimes hives erupt, and then sometimes mild GI symptoms. My stomach was a little upset. I felt a little queasy, but sometimes overt, significant diarrhea and vomiting.”
Links
Find Dr. Fitzhugh online
Healthy Skin Show ep. 056: Hidden Lyme Disease And Your Skin w/ Dr. Darin Ingels
High-risk groups for alpha-gal sensitization
Successful Treatment for Alpha Gal Mammal Product Allergy Using Auricular Acupuncture: A Case Series
A Guide for People with Alpha-gal Syndrome
CDC – Products That May Contain Alpha-gal
Health Care Provider Knowledge Regarding Alpha-gal Syndrome
353: Crazy Meat Allergy Triggered By Ticks (Here’s The Deal On Alpha-Gal Syndrome) w/ Dr. David Fitzhugh {FULL TRANSCRIPT}
Jennifer Fugo (00:14.939)
Dr. Fitzhugh, it is such a pleasure to have you back on the show and for such a fascinating topic, welcome back.
David Fitzhugh (00:21.516)
Thanks, Jennifer. I'm excited. I hear we're going to talk about alpha-gal today.
Jennifer Fugo (00:24.987)
We are. So for those who are like, what is that, alpha-gal syndrome? What is an alpha-gal allergy, and how is it triggered?
David Fitzhugh (00:35.788)
Yeah, so first of all, that was allergists’ reaction at alpha-gal in the beginning. Like, what is this? This is such a strange phenomenon. So alpha-gal is an allergy to mammalian meat. Sometimes we think of it as an allergy to red meat, but, you know, red meat is kind of a more narrow term. So non-primate mammalian meat, think things like beef and pork predominantly in the US. And strangely, it has a few characteristics that are very different than most food allergies. If you think of peanut allergy as the canonical food allergy where you eat peanut and if you have the allergy, you usually have symptoms very quickly and it's very obvious. And those symptoms are typically skin symptoms like hives, and/or coughing and wheezing, and maybe GI symptoms. But the key point is it happens quickly and it's obvious.
Alpha-gal violates that rule. So number one, it takes at least a couple of hours to show up between the time that you might eat beef or pork and when you might develop alpha-gal allergy symptoms. Sometimes it could be as long as eight hours, sometimes even longer. So it's kind of hard to put it together. Like, why would this meat I ate hours ago be causing me to have what seems like an allergic reaction? That's one weird thing. The other kind of obvious, very strange thing is you have to get bitten by a certain kind of tick called the Lone Star tick, it has a little white dot on its back, to develop this alpha meat allergy. Now, it doesn't mean everybody who gets a Lone Star tick bite will develop it, but it's necessary, but not sufficient, to develop this.
And then lastly, we talked about it sort of on the pre-call a few minutes ago, and almost all food allergies that we know of are to protein in the food, whereas alpha-gal is a sugar, a carbohydrate residue, that kind of decorates the fat of meat. So while the allergy itself is to alpha-gal, which more properly is galactose alpha-1, 3-galactose, let's just call it alpha-gal, it's much easier, the sugar sort of decorates the fat, and so it's more concentrated in fatty meats, which tend to be more of a problem. But having a significant delay in onset, not being a protein, but rather sugar, and requiring a tick bite, are all just really weird things for a food allergy. And you know, until about 10 years ago, maybe 12 years ago at this point, it really had not been well described.
David Fitzhugh (02:54.445)
And so if you'd taken a visit to an allergist in, say, 2008, 9, 10, and you'd said, well, gosh, it's so strange. I've had these weird hives that come on three, four hours after I eat a McDonald's pork sandwich, or pork biscuit. An average allergist, a well-informed, educated allergist, would have probably said, yeah, that's really weird, but that's not an allergy, I don't know what it is. So you maybe have chronic hives, maybe something else is going on. So I think our knowledge of food allergy, broadly speaking, but particularly some of the paradigms that the diagnosis of food allergy has rested on for 50-plus years, have really been changed with alpha-gal, which makes it all the more interesting.
Jennifer Fugo (03:31.771)
And I wanted to ask you, because you mentioned about the Lone Star Tick, which some of my listeners may remember a couple years ago, I ended up getting bit by a Lone Star Tick and it hung out on me for five days before I found it. And it was carrying Rocky Mountain Spotted Fever. It feels like a name of a song. And so is the Rocky Mountain Spotted Fever part of the problem here?
David Fitzhugh (04:00.172)
No, not as far as we know. It's a really interesting question. And so when when you hear about ticks, you think about tick-borne diseases like RMSF that you mentioned, also Lyme disease. These are infectious agents that are getting transmitted to the body. That doesn't seem to be what's happening here, and we're not actually 100% sure since it's been described. But what seems to be happening is you get bit by this Lone Star tick, and of course, there's a tiny amount of tick saliva that effectively gets injected into you. And your body starts making allergy antibodies against tick saliva, weirdly enough. And there's enough crosstalk between what tick saliva looks like and what the alpha-gal sugar looks like that when you then eat mammalian meat down the road after your body's had probably at least four to six weeks to make these allergy antibodies, it's sort of, it's like a molecular mimicry. It recognizes the alpha-gal. So it's something about tick saliva that looks close enough to that sugar on mammalian meat that seems to create this crosstalk. But it's not an infection that's being transmitted, and it's not something that you would take antibiotics for, et cetera. It may be obvious, but just to clarify.
Jennifer Fugo (05:07.613)
That's really helpful in understanding this alpha meat allergy. And you had shared with me, I thought this was fascinating, the kind of origin story of alpha-gal mammalian meat allergy didn't really originate with ticks. Would you mind just giving us a little backstory on how exactly did we even learn about this tick meat allergy?
David Fitzhugh (05:24.363)
Yeah, it's really a fascinating story. So there was a tick side on one side, but there was another side of the story, which is there's a chemotherapy drug whose generic name is cituximab, the trade name is Erbitux. And this drug was being infused into some patients, and occasionally people were observing serious and immediate reactions. It's an IV infusion drug. And interestingly, this drug is a biologic drug, a big protein molecule and antibody, but the stabilizer for it was the sugar, alpha-gal. So that was what they used to keep the molecule intact. And these patients, who we have ultimately discovered have alpha-gal, were having immediate reactions. But remember, they were getting it infused in their vein and so it wouldn't be too surprising.
So that was interesting and there were some case reports published about that and I don't think anybody really understood at that time. But roughly simultaneously there was a population of deer hunters in southwestern Virginia who kept coming to the attention of some really smart allergists, most notably Tom Platts-Mills at UVA, and they kept presenting with strange anaphylaxis. Didn't seem to be immediate, there didn't seem to be an obvious, clear, one-to-one trigger like peanuts or shellfish that we might think of. But, you know, Dr. Platts-Mills and his colleagues sort of put this together and said, well, what are they guys doing? They're hunting deer, obviously, deer hunters, and they're typically eating their kill. That's typically what they do, store all this deer meat away in the fridge, and they're getting lots of tick bites as well. And so the reports about the chemotherapy drug were coming out about the same time, and ultimately they looked, and through sort of a tortoise scientific force, they discovered that both populations of patients were allergic to this sugar residue. And there's been some really interesting publications since that time. But it's just kind of a fascinating epidemiological backstory of really racking our brains for what could be the links here. And it turns out the link was the sugar molecule.
Jennifer Fugo (07:23.804)
Yeah, and I wanted to ask too, because you brought up about the hunters, who is most at risk for alpha-gal mammalian meat allergy? And I ask this because when I was looking through different documents, I found this pretty recent report released from the CDC in July of 2023 saying that 42% of surveyed healthcare practitioners had never heard of alpha-gal syndrome, which I felt was kind of surprising. But you say, because you deal with this a lot, that that's not surprising to you. So this is really important. I feel like we're doing like a really important service to everyone because this could be crucial for somebody to hear this and maybe avoid being misdiagnosed or blown off.
David Fitzhugh (08:10.731)
Absolutely. I think there's certainly more awareness now than there was, you know, 10 or even five years ago. But in terms of the at-risk population, a couple of things that are pretty clear. Number one, you have to live in an area where the Lone Star Tick is prevalent. And that's not everywhere in the US. That tends to be concentrated in the southeastern states. Although I was literally just looking for the call and how far it actually has gone, as far north into where you live, sort of Pennsylvania, et cetera. So even past the mid-Atlantic and as far south as the continental United States extends, Florida and beyond. And as far west as roughly kind of eastern Texas. So basically think of the eastern third of the US is where it is. But it's really centered in the southeast, right here in North Carolina, South Carolina, I think it is the alpha-gal belt and you know it's at least once or maybe twice a week diagnosis that I see.
So yeah you have to live where the tick is prevalent, number one. And number two, you know the typical person that we might see with alpha-gal tends to be someone who spends a lot of time outdoors because those are people that are getting tick bites. You know, hunters that we've already talked about, but even just frequent outdoors people that like camping, hiking, that kind of thing, they're certainly all at risk. And again I'll reinforce, of course, not everybody who gets bit by Lone Star Tick develops alpha-gal. It's a necessary cofactor, but it's not the only thing. And we don't necessarily understand the other cofactors that play into it. But, you know, outdoor kind of people and living in the southeast are probably the two biggest cofactors.
Jennifer Fugo (09:40.261)
And is there a particular age range that tends to be impacted more by alpha meat allergy?
David Fitzhugh (09:48.255)
Yeah, it's usually someone in the middle of life. So unlike most other food allergy that we tend to think of, not exclusively, but we tend to think of as a pediatric problem, peanuts, tree nuts, dairy, egg, et cetera, this is usually a 40 to 50-year-old who has no significant allergic history and who says, hey, I've been eating beef and pork my whole life and this strange thing has been going on over the last six months. It is not impossible for a child to have alpha-gal syndrome, but it's relatively unusual overall. And I'd say 90 plus percent of alpha-gal allergy patients are middle-of-life adults, 35 to 50-year-olds.
Jennifer Fugo (10:29.629)
And so, one thing I was looking at in the literature before our call today was about the kind of like, how does this happen? And one of the things that I found most interesting, and this was actually in a paper that I'll put into the show notes, is that, quote, repeated tick bites were shown to increase the likelihood for alpha-gal sensitization regardless of the age of the individuals. So do you feel like that could be a factor? Like you were saying, people who are outside a lot probably have a greater risk of more tick bites than someone who isn't all that outdoorsy or doesn't work outside or doesn't hunt. So do you think it's repeated exposure? Because I don't want people to go, oh my goodness, I got bit by this tick, now all of a sudden I could develop this alpha meat allergy. I sort of want to help them understand the complexity to this.
David Fitzhugh (11:21.343)
Yeah, well, we're still struggling to understand all the complexity, to be quite frank, but I would say that someone who gets multiple Lone Star tick bites is definitely at higher risk. Then again, you could have a single tick bite and ultimately develop this, but people who get repeated tick bites tend to be the ones who often have, not necessarily more severe reactions, but lower thresholds. So, meaning, if you get these repeated tick bites, you tend to drive this allergy antibody, what we call titer, so the amount of allergy antibody in your bloodstream, you tend to drive that titer higher and higher. And the higher the titer, not necessarily more severe reactions, but lower thresholds. And so patients with very high alpha-gal IgE or antibody titers, these tend to be the ones that have to avoid, and this is a good segue into, hey, how do I manage this? How do I avoid it? But these tend to be patients that have to avoid multiple sources of alpha-gal.
Now, the average patient, about 85, 90% of alpha-gal patients, just need to avoid mammalian meat, beef, pork, but other potential sources, if you're someone that likes to go to Ted's Montana Grill and have a bison burger, bison, venison, even rabbit is mammalian, you would need to avoid those. But there's this small minority of very high titer patients, probably 10 to 15%, who really have to avoid a whole host of other things that we can get into.
Jennifer Fugo (12:39.257)
Yeah, and let's get into that in a moment because I just want to make sure to clarify, because you've mentioned a couple of times about this titer. So is there a specific test that is now used to determine this or do you just use the clinical alpha-gal allergy symptoms and presentation?
David Fitzhugh (12:58.507)
I would say the clinical history is always most important to an allergist, and probably with 90% accuracy, having heard these stories over and over again, we can diagnose it. But it's not always simple. I mean, someone who gives me a story of, hey, four times in a row I had meatloaf and six hours later woke up covered in hives and vomiting in the bathroom, that's pretty clear cut. But sometimes patients have more of a story of almost like a chronic urticaria story or chronic hives. And while we don't typically think of alpha-gal as necessarily an underlying cause, once in a while does seem to be a contributor to chronic hives or just chronic itch at low levels.
So, yeah, the definitive test is a blood test that is now pretty standard in the US that you can run off and get a specific level of alpha-gal IgE, IgE being the allergy antibody, but there's an alpha-gal specific IgE that can be run. And if that's positive above the detection threshold, which is generally 0.10, and you have a compatible clinical history, that would make the diagnosis. We don't typically do skin testing on this the way we might for many other allergies. Skin testing is available in research settings, but it's something that's sort of messy and not easy to do for alpha-gal in particular. But the blood test is easy and run by commercial labs.
Jennifer Fugo (14:12.873)
And you mentioned alpha-gal allergy symptoms that include hives and itchiness. There's some, it sounds like, GI issues, like you could vomit up the food. Would alpha-gal syndrome cause maybe diarrhea and cramping? And so what are some of the alpha-gal allergy symptoms? And then also, could this cause anaphylaxis?
David Fitzhugh (14:39.819)
Yeah, I'm glad you brought that up because it does differ in what we think of as reaction phenotype, meaning what does this patient look like when they have a reaction? You could have anaphylaxis, true life-threatening anaphylaxis, including airway closure and that kind of thing. You could, but it's really rather uncommon in alpha-gal syndrome, and there's maybe a few reasons for that we can get into, but most typically it's skin and GI symptoms. So these patients often, because again, there's a typical at least four-ish hour delay, sometimes longer, they'll often tell us about waking up in the middle of the night with hives or GI symptoms. It's pretty rare in my experience to have significant respiratory symptoms, though it can happen and I don't want to suggest that it couldn't. But it's usually skin.
Patients, in my experience, they have this sort of palmar-plantar itching, right? They complain of itching on the palms of their hands, soles of their feet, and then sometimes hives erupt, and then sometimes mild GI symptoms. My stomach was a little upset. I felt a little queasy, but sometimes overt, significant diarrhea and vomiting. But those two systems are by far the most affected. As you can imagine, if you had just the GI symptoms and you didn't have many skin symptoms, you might just say, I ate something bad or food poisoning, that kind of thing. It'd be very easy to attribute it to something that was not allergic in nature. And plenty of patients do have GI-only alpha-gal allergy symptoms. So that, in addition to the significant prevalence of GI symptoms, if you couple that with the delay and onset, you can see why this is kind of hard to recognize.
Jennifer Fugo (16:13.693)
I can see that, because you could blame it on a bunch of different things. You could also potentially just assume that it was a beef allergy and not realize that it extends to other mammalian proteins (alpha gal mammalian meat allergy).
David Fitzhugh (16:22.407)
Yeah, that's a really interesting concept. Like, could you be allergic to beef protein and not have alpha-gal syndrome? You could. We don't see that very often. One interesting, and this is almost like an allergist nerd trivia question, but one interesting distinguishing thing we see once in a while, there's a fascinating phenomenon called pork-cat syndrome. So these are patients that are allergic just to pork, and they are allergic just to pork because they have strong cat, like cat hair, allergies. But a minor allergen in cats, so not the main allergen, but some of these patients are sensitized to a minor allergen in cat, it's called Fel d 2 for the allergist nerds out there, but Fel d 2 cross-reacts just with pork.
But what's important, and we will ask patients about this when we think about alpha-gal, pork-cat syndrome, in my experience, is really rare. Maybe I made the diagnosis once or twice in my pushing 15-year career now, whereas alpha-gal syndrome, once or twice a week. But two distinguishing features. One is alpha-gal is the entire spectrum of mammalian meat, number one. And number two, it's delayed. If you have pork-cat syndrome, it's just pork, you can eat beef just fine, and it happens quickly because it's still to a protein allergen. But that would be one potential confounder.
I think much more, pork-cat syndrome is sort of an academic interest thing, but putting that aside, much more likely is just attributed to, I had a viral gastroenteritis, or I had food poisoning, or just some random bug that caused me to, you know, people sometimes get hives with viral infections too. So there's all kinds of diagnostic delay in making this diagnosis until you see an allergist who knows a lot about this. Although I would like to think most of us know a lot about it now. And, I think at least in the Southeast, the average primary care doctor at least has heard of this and the ER generally knows about this as well.
Jennifer Fugo (18:19.543)
So it sounds like delay is a key word here, right? So am I hearing correctly that having the bite or getting bit by a tick, it's going to take time, right, to become sensitized to the saliva? Gosh, it's kind of gross when you think about it, but the saliva that it injects into you, it's going to take several weeks, right, to know if you have an issue with tick meat allergy.
David Fitzhugh (18:39.691)
It is. Yeah, you got that right.
Jennifer Fugo (18:50.269)
So it's not like you got bit by the tick on Monday, and by Saturday, all of a sudden you're having these types of alpha-gal allergy symptoms.
David Fitzhugh (19:05.035)
Definitely not. Yeah, we would think that, and that's maybe a separate delay, not the delay between eating meat and symptom onset, but getting bit by a tick and actually starting to make IgE to the tic saliva, which is alpha-gal IgE. That delay, probably honestly at least four to six weeks. And so when I'm asking patients about past tick bites when I'm thinking about alpha-gal syndrome, my experience is, first of all, even though many ultimately wind up having a clinical diagnosis of alpha-gal, only about half remember a tick bite at all. And I usually use arbitrarily like, hey, do you think you've been bitten by a tick in the last two years?
I mean, because one of the other things about alpha-gal syndrome is, there's so many things that are so strange and odd, right? Delay, tick bite, carbohydrate allergen, but also it's really inconsistent. Like you can have this allergy, proof positive on the test, no doubt, and you could have five reactions in a year, but eat beef or pork three times a week. Why should that be? It's strange, right? We can talk about it, but the sort of short answer is there's a dose dependency to this. So some people are just not quite reaching the threshold that causes them to tip over into a reactive state. Alpha-gal is concentrated, so again, it's a sugar residue, but it's concentrated in the fat of meat. So there are patients with kind of low-level alpha-gal who get away with eating kind of lean cuts of meat, even though it's still mammalian meat, but they're eating lean cuts, they do fine. But if they say a 70/30 ground chuck, which by definition is 30% fat, they're going to have a big problem.
David Fitzhugh (20:20.585)
Lard is a common thing in the South. People like to cook with lard, which is beef fat, other kinds of mammalian meat fat. And it's just pure fat, right? So sometimes I hear stories of someone who has known alpha-gal. Like, hey, I went to my grandmother's house for Thanksgiving, lovely meal. And of course, turkey is not a mammal. So poultry, fish, shellfish, should be fine for alpha-gal syndrome patients. And they say, gosh, I had a great turkey dinner, but then I had a clear reaction three hours later while we're watching football. What happened? Talked to my grandmother. She says, “ah, but I love to make this gravy with beef fat”, you know? And that can get you, right? It doesn't seem like a lot of gravy, but it's concentrated in the fat, so it can be a problem.
Jennifer Fugo (21:00.821)
I love that you're sharing about that because I do think we should talk about the foods and where else to find this. So you said poultry, so chicken, turkey, pheasant, those types of things would be okay for alpha gal mammalian meat allergy.
David Fitzhugh (21:06.121)
Yeah, they should be fine.
Jennifer Fugo (21:07.248)
Eggs, eggs are good. Shellfish and fish generally.
David Fitzhugh (21:08.831)
Yeah, eggs are fine. Should be all fine.
Jennifer Fugo (21:10.846)
I did read that some tuna you have to be careful with, because if there is dolphin or whale that somehow got in there, that could be an issue. That's what I read. I'm going to put the reference into the show notes.
David Fitzhugh (21:32.921)
I'd have to investigate that as a trigger for alpha-gal allergy symptoms. That's not something I would actually advise patients generally, but I think where you do have to be careful for some, again, highly sensitized patients who when they take the antibody test are on the higher end of the spectrum, then you start getting to things that we know have alpha-gal, but at low levels. Most prominent is dairy. So the number one question I get when patients have this diagnosis is to say, well, okay, I understand about the meats, doc, but do I need to avoid dairy?
And dairy, of course, comes from cows, cows' milk. Dairy does have detectable low-level alpha-gal, but the thing is, for the average alpha-gal syndrome patient, it's just not enough to trigger a reaction. And so if you look in well-regarded literature, only about 10 to 15 percent of patients seem to really need to avoid dairy as well. And so it's not the typical advice that every alpha-gal patient should avoid dairy. We would say every alpha-gal patient should avoid mammalian meat for sure. And if you're avoiding mammalian meat, but you're still having symptoms, then I think the next step is to look into dairy.
And then, you know, if you've eliminated dairy and you're still having suggestive alpha-gal symptoms, this sort of delayed reaction kind of phenomenon, then there's the everything else. And the everything else gets complicated. So in that category are mammalian meat byproducts. So gelatin is one, gelatin is made from all kinds of things that you don't want to know about, beef hooves and other things. And there's small amounts of alpha-gal in there. So it can be, someone that has a very high level of alpha-gal, maybe needs to avoid gelatin capsules. We don't think of this as being an issue, but plenty of over-the-counter medicines, vitamins, supplements are made with gelatin capsules. And this can be enough to trigger some alpha-gal patients. So it's a really interesting thing.
Jennifer Fugo (23:31.479)
And I was going to share too, because I had a client, I was telling you before we started, I think it's seven or eight years ago, and it was the first time I had ever heard of alpha-gal syndrome, and I'm always like, I'll figure it out, no worries. It was really difficult at the time to figure out what she could take, because again, like you mentioned, gelatin capsules, any time it says gelatin in the ingredients, that's made from beef. So I learned very quickly, I had to call supplement companies, because they really don't, they check for the top nine allergens, but this is not one of them. And so they sometimes can't quite tell you, that's where you sometimes are better off doing like vegan or vegetarian supplements, because there's a better chance that they'll be hopefully safe.
But even some things like magnesium stearate, which can be a filler where it'll help the flow and filling, sometimes that can be an issue. Collagens, because obviously if collagen is coming from a mammalian protein like beef, that's an issue. Also remember, too, for everybody listening, pancreatic enzymes that you may supplement with would also be a problem, so you'd have to look at your digestive enzyme formula. And then any type of hormonal glandular supplements, so things that support the adrenals or thyroid, if it is a glandular or those liver capsules or organ meat capsules are all no-goes. So it is important to really dig into your supplements. And I did want to ask you, what about whey protein powder or casein? You said dairy might be okay. What do you think about those?
David Fitzhugh (24:53.546)
Yeah, I think for most patients that probably is going to be okay in the sense that they should be protein supplements and so you probably should not be, as isolated protein supplements, I doubt they'd have much alpha-gal in them. But it's certainly not impossible, and some of that depends on processing and manufacturing, that you just have really very little control or knowledge over. I just want to be clear for your listeners, though, there are lots of potential esoteric sources of alpha-gal, like you've mentioned, in gelatin, pancreatic enzymes, other things. Carrageenan is another one that's sort of become recognized recently. Carrageenan is actually, strangely, not an mammalian meat product. It comes from red seaweed, but it has sugar residues that look close enough that seem to be cross-recognized, and it's used as an emulsifier, thickener in lots of food products. But dairy, gelatin, carrageen, and all of those things, the majority of alpha-gal syndrome patients do not need to avoid those, and dairy as well. So I don't want the listeners to think that, gosh, I have to avoid this laundry list.
The way to approach it, I think, at least somewhat scientifically, is, if you do have a diagnosis of alpha-gal syndrome, strictly cut out the mammalian meat first, and that should be your guidepost for at least the first 8 to 12 weeks. And if you're doing well, you're doing well. But if you're still having symptoms, then you start iterating down the list that you mentioned. By way of contrast, I also want your listeners to understand there definitely are patients that need to avoid these more, think of them as minor alpha-gal sources, but I don't think you should start avoiding all of those with the initial diagnosis, because then it'll make you crazy and you may not need to avoid all of those, is the point.
Jennifer Fugo (26:48.382)
Exactly. I just wanted to list out to everyone, I made a list, because I thought this was helpful too, because I think of just cow, pig, goat. And then I was like, oh, but venison. And like you mentioned in the beginning, bison is an issue. Rabbit, bear, sheep could be lamb or mutton. And then obviously organ meats. So these are sort of the big overarchers that probably you're going to encounter most commonly. And I think sometimes we only think of what feels obvious and we forget about some of the others. And then I also noticed, so we have that cetuximab, is that correct? That drug. And then also heparin may also be an issue if you have a tick meat allergy.
David Fitzhugh (27:35.462)
Yeah, it's interesting, so most heparin in the US, although there are non-porcine heparin, most heparin in the US is used as a blood thinning agent and would be used after a heart attack and for other issues to thin the blood and prevent clotting issues. Most of it is pork-derived, so porcine-derived. And in theory, there could be small amounts. But in talking and in reading from Scott Commins, Scott Commins was one of the deputies of Tom Platts-Mills who is probably now the leading knowledge base of alpha-gal, but their clinical experience is actually very few alpha-gal patients have any issue with porcine heparins. So it's not something they worry too much about apparently.
There are things that could have more though, so heart valves that sometimes are porcine-derived often have alpha-gal on it. That could be an issue. I think the other things you mentioned are all interesting, but getting back to like, hey, what's the main source and what are all these other animals? As I describe it to patients, I try to keep it simple. I just say, anything with four legs or anything with hooves, that should cover most of your bases. Four legs or hooves, you avoid those you’d probably be good.
Jennifer Fugo (28:44.439)
So the big question is, is there a treatment for alpha-gal syndrome? Can alpha meat allergy be cured or stopped or reduced? What can you do?
David Fitzhugh (28:50.79)
Yeah, there's no clearly recognized treatment. Before the call, we were talking about, I think a chiropractor, if I'm not mistaken, in Tennessee somewhere who offers this auricular treatment where he just inserts a small needle into the auricle, which is sort of the outer part of the ear. And for some reason, some people have had success with that. And again, alluding to our little pre-call before, I don't have any explanation mechanistically why that should work. I don't think it would be harmful, but I also wouldn't put too much stock in that it should definitely work for all patients. Perhaps it's worth a try for some patients.
But for the average patient, the management is simply avoidance of mammalian meat and perhaps the other alpha-gal sources if those trigger you and your particular alpha-gal allergy symptoms, and time, and not getting bit by ticks. We know that on average people will decrease their alpha-gal titer just over time if they don't get new tick bites. Time to quote-unquote lose or, I don't know if outgrow is the right term, we think of that more as kids, but time to resolve an alpha-gal allergy is not infinite number of years, but in my experience, you know, three to five years, starting with kind of middle of the road alpha-gal levels, you know, when you were first diagnosed. But that presumes no new tick bites, right? If you get another alpha-gal tick or another Lone Star tick bite in that interval, kind of all bets are off and that might spike right back up.
And by the same token, someone could completely resolve alpha-gal. You know, hey, you had the problem for two, three years, I saw you last year, blood level undetectable, I got mammalian meat back in my diet with no issue. But you know what? A year ago, I got another tick bite, and now I'm starting to have crazy reactions again. Like, it can come back. So it's the tick that drives it, unfortunately. And for a lot of people that enjoy outdoor lifestyles, it can be hard to avoid tick bites, even doing DEET and other repellents. It can be tough.
Jennifer Fugo (30:47.35)
And so I guess this also underscores, and this was my learning lesson, getting the tick between two of my little toes. I know, I should have looked and I was probably wearing flip-flops, I was in Maryland. So I was in one of those states where they do have a high rate of ticks and I didn't realize it until five days later that it was there. So obviously doing tick checks as best you can. I guess the issue is really the initial bite. Is that correct? So whatever comes afterwards in terms of an infection is like a secondary issue or another problem potentially.
David Fitzhugh (31:28.037)
Yeah, and really I would say another unrelated problem. But yeah, after the initial bite, again, it would probably take between four and six weeks if you're someone who is predisposed to developing alpha-gal. And there's just other co-factors we don't understand, again, because many, many people get Lone Star tick bites, and don't develop clinical alpha-gal syndrome. But if you're going to develop it, it'll probably take at least four to six weeks to start developing these antibodies and see clinical symptoms.
One other thing I’d point out to you, I mean, I totally agree with you that trying to be diligent about tick checks after you've been outdoors, certainly good practice, but one of the challenges is the Lone Star tick can exist in this larval or seed tick form that doesn't look like your classical embedded tick. So sure, when you think about, oh, it's a tick embedded in my skin, it's fairly obvious. But you can just walk through tall grass and get what in the south we would call chigger bites, you know, just a little bunch of itchy sort of no-see-’em things, and think you're good, never see an embedded tick, and develop alpha-gal, because Amblyomma, or the Lone Star tick, exists in this larval or seed tick form, and you never pull off an embedded tick. So many, many patients have no memory of any quote-unquote true tick bite and yet still develop alpha-gal.
Jennifer Fugo (32:46.967)
So wait, are you saying that the chigger bites, is there a connection between them? Or it just looks like you got all these little bites?
David Fitzhugh (32:54.18)
Yes, the latter. So not that chiggers are not the same organism, but just that it can feel like you got a few chigger bites and not actual tick bites, but actually those were larval tick forms of the Lone Star tick that no one would recognize and then don't leave an embedded tick. But yet that can still be enough to drive alpha-gal allergy symptoms. So it's another sort of mystery about this.
Jennifer Fugo (33:19.831)
This feels, like you said, a very different experience from a lot of these other allergic responses.
David Fitzhugh (33:25.666)
Oh yeah, I mean I always tell patients when we're talking about this diagnosis, first of all, they don't look like typical allergy patients, right? It's a middle-aged, you know, male who walks through the door who’s a robust outdoor person, never had allergies or hay fever or eczema their whole life, which is what we think of as much more the sort of classical allergic triad. I think this weird thing is happening, and we talk about it and sometimes that alpha-gal story comes to light very easily. So yes, it's very strange.
We didn't talk too much about why the delay. But it has to do with how fat is digested. So fat is not processed straight from the GI tract into the bloodstream. Fat actually gets put into these things called micelles, and that actually crosses into the lymphatic system first. And the lymphatic system has its own kind of slow circulation, sort of percolates back up into this thing called the thoracic duct, and then gets dumped into the bloodstream after it's kind of gone to the lymphatic system. So because fats have this unique way of getting digested by the human body, and alpha-gal’s really concentrated in the fat. Again, it's a sugar, but it's attached to the fats, that's why we think this delay happens. At least that's the postulated mechanism, and it makes sense.
Jennifer Fugo (34:46.334)
That is so fascinating, because I also, you know, I'm working with so many people who have GI issues. Some people can’t break down fat very well. So that's just interesting. Oh my goodness. I feel like we're clearly not at the beginning of understanding alpha-gal, but I don't think we're at the end. It sounds like there’s a lot more to learn from this.
David Fitzhugh (35:04.294)
Yeah, well, I think there's more to learn from alpha-gal specifically as a clinical entity, but I think the other thing that you've touched on, and I think is worth reinforcing to your listeners is, you know, this has changed some of the paradigm in the food allergy world, but one of my core expertise is dealing with severe food allergies typically in kids. And again, we think of them as scary, immediate peanut anaphylaxis. That's what food allergy kind of looks like, or at least we thought we knew that. But clearly there's different kinds of food allergy that are going through at least somewhat different pathways, and that can look differently. And my kind of attitude with the evolving knowledge of alpha-gal is, well gosh, if alpha-gal is out there, surely there must be other interesting food allergy mysteries that we don't totally understand, and that as we begin to unravel the alpha-gal mystery, it may help us unravel other mysteries. So it really has, I think, broadened some allergists’ horizons and, you know, we're thankful for that, although it's one of those occasional situations where I feel like the more I know, the less I know, which can be frustrating, but keeps life interesting.
Jennifer Fugo (36:09.95)
Well, thank you so much for sharing all of this today. I love the fact that you had actually brought this idea to me to have on the show, which I was again somewhat familiar with because I've worked with one client ever who's had this. And as I dug into it, I'm like, this is really important because this does have GI symptoms. It has skin symptoms. It could be something that could be difficult to tease out, maybe.
And to your point, for someone who, maybe, their vacations tend to be going to national parks and they went hiking up the Appalachian Trail or something, but they live out in California, they might not be super familiar if a doctor out there is looking at these weird presentations and going, I don't know what to make of this. It doesn't make any sense. And so like I said, I think this is a really tremendous, important topic to get out there so that people can start to think about also how to share their case to a doctor to help it make more sense. Because I think sometimes we also disregard pieces that we think don't matter. But in this instance, maybe that individual might go, oh, by the way, this past summer, three months ago, I was out hiking through Appalachia for two weeks and, you know, we were in a tent and all doing all the outdoorsy things. And I did actually get bit by a tick and didn't think anything of it.
David Fitzhugh (37:26.758)
Yep. Absolutely.
Jennifer Fugo (37:32.926)
So anyway, I just want to thank you so much for being here. I'm going to make sure to link up your practice in the show notes because I know that we have many listeners who are in, you're in the North Carolina area, is that correct?
David Fitzhugh (37:49.222)
That's right, Chapel Hill, North Carolina, so go Tar Heels.
Jennifer Fugo (37:59.761)
Yes, perfect. And thank you so much for being back on the show, Dr. Fitzhugh. I really appreciate your time and also your enthusiasm in sharing these types of topics, which really for many people could be very life-changing. And I'm so glad that we can do this together.
David Fitzhugh (38:07.718)
Yeah, thanks so much. I really enjoyed connecting and just by way of summary, I totally agree. It's been a strange journey in the alpha-gal world, but I think it's really been incredibly enlightening both for us intellectually as allergy professionals, but also as a eureka moment for many, many patients who had no idea what was going on before. So it's a really great story to tell and to share.
Jennifer Fugo (38:29.662)
Thank you so much for being here.
