Welcome!! I deal with shellfish, and I created a thread that can be easily found to talk about cross contamination avoidance.  Here it is:
Tips for Avoiding Cross Contamination with Shellfish

So glad you got it narrowed down and can now focus on an avoidance plan!

There are lots of good suggestions for avoidance in the PA/TNA and Fish/Shellfish sections of the board.  Also reading in Restaurants and Manufacturers will give you a sense of which companies are better than others and good dining out techniques.  And, as always, feel free to ask questions as they come up!

Were you able to pinpoint what caused your reactions?  We can probably help you work through what/how/why and how to prevent the type of behavior/situation that led to the reactions.

Also, did your doctor give you a plan so you know exactly when to use the EpiPen?

I'm back! Thanks for your input/advice/everything - I think I've finally gotten some answers now. I got in to see an allergist and got a Cap-RAST test done, plus a couple food challenges.

At this point, I'm "officially" allergic to shrimp, lobster, crab, walnuts, and pecans, so I'm avoiding all shellfish and most tree nuts right now. I've also been prescribed an Epi-Pen.

I guess at this point what I'm looking for is tips - avoiding cross contamination, etc. I've had a couple reactions in the past few months and I'm trying to find ways to avoid more reactions. Input/advice is welcome! Thanks.

Yes, I'm talking botanically related.  If you're allergic to several nuts, it would be more probable to be allergic to those that are "cousins" - walnuts/pecans, cashews/pistachios, hazlenut/filbert/hickory nut. Almonds are related to pit fruits (peaches, plums), and pine nuts are seeds.

So, you test positive to walnuts. The cookies likely contained walnuts. Are you allergic? It's seeming more likely. When you ate nuts every few weeks, we're they usually walnuts or other unrelated nuts?  If they were walnuts, then it could be possible that you only reacted this time because your system was primed from the shrimp reaction, but obviously you don't want to test it out on your own!  Hopefully you have an allergist who is experienced with food allergies and up to date research and (s)he can help you find out for sure. Since both shellfish/fish and tree nuts are often cross-contaminated, you'll want to avoid all until you know.

(I'm taking notes about all the stuff I should be doing to narrow down my actual allergies.  )

That's interesting what you said about the various nuts not being related to each other - did you mean that certain nuts have similar structures and therefore if you're allergic to one you're also probably allergic to one with a similar structure?

I'm hopefully getting into the allergist's office in the near future and I'll see about scheduling a Cap-RAST.

I don't know what would technically count as "often" but I'd have nuts maybe a once every few weeks - most often in trail mix or similar. I called my friend regarding the cookies and if she's remembering correctly, they did, in fact, have walnuts in them.

The shrimp reaction was before the mystery reaction.

Unfortunately, testing cannot predict the severity of a reaction, just the likelyhood of one.  There is new component testing that tests for specific proteins in certain allergens that has been found useful in predicting whether an allergic person is likely to suffer a severe reaction, but it is only available for a few allergens at this time. If you search in Main and Research, you should be able to find some recent threads about component testing.

Yes, you are correct - peanuts are not actually nuts. However, it may be difficult to find peanuts that aren't contaminated with nuts.

Also, I find your positive nuts to be an odd assortment because walnuts are not related to cashews or pistachios (though I believe those two are related and to mango as well). Pine nuts, I believe, aren't really nuts but seeds. It would be unusual to be allergic to that particular grouping. I think it's definitely worth further investigation to see which nuts you may actually be allergic to.

There is a blood test called Cap-RAST that might be useful in narrowing down the true positives. With my son, we compared the results of the SPT and RAST tests and the results that were similar we felt were the most likely to be accurate. From there we worked with the allergist to confirm the true allergies through a series of food challenges.

Did you often eat nuts?  Did the cookies have nuts?  If so, can you find out from your friend what kind?  If you often ate nuts and the cookies had no nuts, it would be pretty rare to have your first reaction to cross-contamination. If so, that probably tells you that you have a low tolerance and need to be extra careful.

Also, did you have the mystery reaction first or the shrimp reaction?  Sometimes after a reaction our bodies are primed to react and will show symptoms to things you are normally fine with.

Thank you so much! I did not know that about the SPT false positives. It's good to know that I'm not necessarily allergic to ALL the things I tested positive to. I have been avoiding all shellfish and all fish for now - I tested positive to cod, trout, and tuna in addition to the shellfish I tested positive to.

A couple more questions I just thought of - does the SPT tell you "how" allergic you are to something? Because some things had a much larger positive reaction than some of the other things I tested positive to and I didn't know if that was any kind of prediction of the severity of the allergy.

Also, with the nut thing - I'm pretty sure I already know the answer, but peanuts don't technically count as nuts, right? I tested positive for cashews, walnuts, pine nuts, and pistachios and am avoiding all nuts to the best of my ability as per the doctor's orders, but am I correct in assuming that peanuts aren't actual nuts?

Regarding the mystery reaction...hmm. Trying to remember what I ate beforehand. If I remember correctly, I think it may have been after eating cookies that a friend made - which I suppose is a highly likely source of nuts. Hmm.

First of all, welcome!  I'm sorry you needed to find us, but I'm glad you're here

Secondly.  I think it's important to know that SPT is only about 50% accurate for positive results (and about 90% accurate for negatives), so that means that it's likely you're not really allergic to everything you tested positive for.

Since you most likely reacted shrimp, I would believe that result as well as the other shellfish results.  Since fish is often contaminated with shellfish and vice versa, I would also avoid the fish you tested positive for.  As for avoiding all fish, that's something you'll have to decide as you become more familiar with your allergies and develop a comfort zone.

Have you ever reacted to nuts?  If not, I'd request an in office food challenge for them. 

As for your mystery reaction, what had you eaten in the 4 (or so) hours prior?  Could it have been contaminated with fish or shellfish?  Nuts?  Prepared at home or out?  If you can figure out what the most likely culprit was, that will help you in avoidance as well.

As you read here, I'm sure you'll have lots of questions.  Feel free to ask away!

Hi -

Just found this forum and I'm really glad I did! I'm 20 years old and in my third year of college, and was just diagnosed with food allergies for the first time in my life. Although I've had bad environmental/seasonal allergies and mild asthma ever since I was a kid, I'd never had any signs of food allergies until recently.

Then in the last few months I had two allergic reactions, both presenting as hives and some minor facial swelling; they both resolved with Benadryl. One was almost definitely a reaction to shrimp, but I don't know what I reacted to the second time. Long story short, I had an SPT a couple weeks ago, and in addition to shrimp, I also tested positive to lobster, crab, several kinds of fish, and several different nuts. 

I've been slowly starting to figure out about reading labels and learning about cross contamination and everything, but I have to say, I'm feeling a little overwhelmed right now about all these foods I'm newly allergic to. 

Any words of wisdom and/or advice to make the learning process a bit easier? Thanks!