# Sulfa drug allergy: cross-reactions? **URL:** \ **Category:** Factual Questions\ **Created:** [June 2, 2003, 3:16am UTC](https://boards.straightdope.com/t/sulfa-drug-allergy-cross-reactions/179058 "2003-06-02T03:16:53Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Eva\_Luna](https://avatars.discourse-cdn.com/v4/letter/e/e495f1/32.png) [@Eva\_Luna](https://boards.straightdope.com/u/Eva_Luna)\ **Post date:** [June 2, 2003, 3:16am UTC](https://boards.straightdope.com/t/sulfa-drug-allergy-cross-reactions/179058/1 "2003-06-02T03:16:53Z")
Alright, I know I’m allergic to sulfa drugs (found out the hard way once by breaking out in hives and passing out on the floor of the pharmacy when I went to pick up the replacement prescription). But what other sulfur-related items are likely to provoke a cross-reaction? Specific background (bear with me if I don’t make sense, because I took a Benadryl and I can feel it kicking in right now; I’m getting pretty loopy): I have all sorts of allergies, but no known food allergies. Things I’m sensitive to include the aforementioned sulfa drugs (but no other drug allergies, either), pollen, cigarette smoke, high ozone days, that sort of thing. Almost all airborne stuff, which I can’t avoid in any case for the most part. Today my mom came over for dinner, and I grilled, using a new recipe modified from a Cuban friend of mine. It involved a new ingredient I’ve never bought before: bitter orange marinade. About an hour after dinner, I started itching uncontrollably: eyes, chin, neck, scalp, etc. It drove me absolutely bonkers. Nothing else I’d eaten or otherwise been exposed to was new, so I investigated the bitter orange marinade label, and lo and behold, there it is: 1/50th of 1% sulfur dioxide (preservative). I don’t eat a lot of processed foods - I’m a compulsive label reader and avoid chemical preservatives whenever possible. I took a Benadryl, since the symptoms suggested an allergic reaction of some sort, and I’m starting to feel better (if a bit loopy). So what are the odds that the sulfur dioxide is the culprit? How close is it chemically to the sulfa drugs that I already know I’m allergic to? How can I figure out for sure? (Wine with sulfites has never bothered me, if that’s any help in the elimination process.) ---
**Author:** ![dejahma](https://avatars.discourse-cdn.com/v4/letter/d/839c29/32.png) [@dejahma](https://boards.straightdope.com/u/dejahma)\ **Post date:** [June 2, 2003, 3:41am UTC](https://boards.straightdope.com/t/sulfa-drug-allergy-cross-reactions/179058/2 "2003-06-02T03:41:01Z")
You might want to check this site. Acording to this ref. sulfa allergy and sulfite allergies are not related. I am allergic to sulfa but not sulfite myself. [http://www.uic.edu/pharmacy/services/di/sulfa.htm](http://www.uic.edu/pharmacy/services/di/sulfa.htm) ---
**Author:** ![dejahma](https://avatars.discourse-cdn.com/v4/letter/d/839c29/32.png) [@dejahma](https://boards.straightdope.com/u/dejahma)\ **Post date:** [June 2, 2003, 3:42am UTC](https://boards.straightdope.com/t/sulfa-drug-allergy-cross-reactions/179058/3 "2003-06-02T03:42:35Z")
ps sulfur dioxide is a sulfite ---
**Author:** ![Eva\_Luna](https://avatars.discourse-cdn.com/v4/letter/e/e495f1/32.png) [@Eva\_Luna](https://boards.straightdope.com/u/Eva_Luna)\ **Post date:** [June 2, 2003, 3:45am UTC](https://boards.straightdope.com/t/sulfa-drug-allergy-cross-reactions/179058/4 "2003-06-02T03:45:14Z")
Thanks, **dehjama.** Great site! (I did get to the part aboiut sulfur dioxide; I’m a fast reader.) I guess the only way to know for sure is to see if the leftovers kill me tomorrow, huh? ---
**Author:** ![dejahma](https://avatars.discourse-cdn.com/v4/letter/d/839c29/32.png) [@dejahma](https://boards.straightdope.com/u/dejahma)\ **Post date:** [June 2, 2003, 3:48am UTC](https://boards.straightdope.com/t/sulfa-drug-allergy-cross-reactions/179058/5 "2003-06-02T03:48:37Z")
Having numerous allergies myself I know the Benadryl buzz. Sometimes the B dose is the only thing that helps. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [June 2, 2003, 4:06am UTC](https://boards.straightdope.com/t/sulfa-drug-allergy-cross-reactions/179058/6 "2003-06-02T04:06:46Z")
[Sulfonamides sometimes show up in food items](http://www.google.com/search?hl=en&lr=&ie=ISO-8859-1&safe=off&as_qdr=all&q=sulfonamide+food), despite US laws against such usage. Obviously something like that wouldn’t be listed on the label. ---
**Author:** ![Eva\_Luna](https://avatars.discourse-cdn.com/v4/letter/e/e495f1/32.png) [@Eva\_Luna](https://boards.straightdope.com/u/Eva_Luna)\ **Post date:** [June 2, 2003, 4:10am UTC](https://boards.straightdope.com/t/sulfa-drug-allergy-cross-reactions/179058/7 "2003-06-02T04:10:03Z")
\*\*Squink, \*\* a quick glance at your link seemed to indicate this is more of an issue with animal-based food products. Have you seen anything to suggest it ight be an issue for non-animal-based foods as well? ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [June 2, 2003, 4:46am UTC](https://boards.straightdope.com/t/sulfa-drug-allergy-cross-reactions/179058/8 "2003-06-02T04:46:37Z")
Some pesticides and herbicides are also based on sulfonamides. ([Here.](http://www.google.com/search?hl=en&lr=&ie=ISO-8859-1&safe=off&as_qdr=all&q=sulfonamide+herbicide)) I’m not very well up on Ag-chemicals, and some of these are quite new, but they _are_ used on food crops. Whether that includes bitter orange peels is anyone’s guess. ---
**Author:** ![irishgirl](https://avatars.discourse-cdn.com/v4/letter/i/8edcca/32.png) [@irishgirl](https://boards.straightdope.com/u/irishgirl)\ **Post date:** [June 2, 2003, 11:58am UTC](https://boards.straightdope.com/t/sulfa-drug-allergy-cross-reactions/179058/9 "2003-06-02T11:58:19Z")
Sulphur dioxide is a relatively common preservative. Eva Luna, I would imagine you’d have reacted to some other food items as well, especially jams, jellies and marmelades, as they use this gas in the bottling process. ---
**Author:** ![Eva\_Luna](https://avatars.discourse-cdn.com/v4/letter/e/e495f1/32.png) [@Eva\_Luna](https://boards.straightdope.com/u/Eva_Luna)\ **Post date:** [June 2, 2003, 10:37pm UTC](https://boards.straightdope.com/t/sulfa-drug-allergy-cross-reactions/179058/10 "2003-06-02T22:37:57Z")
Well, my friendly neighborhood pharmacist confirmed that there is not necessarily a cross-reaction between sulfa allergy and sulfur dioxide, but thought it might be worth chatting with my doc and maybe doing some broader-spectrum allergy testing to rule out a wider spectrum allergy issue. (It could have been one of the other preservatives, too, and if I can avoid this hell by avoiding certain foods, I will definitely do so.) Any other ideas?