TB or not TB? That's my question.
January 20, 2011 9:31 PM   Subscribe

My wife and I had injections for a TB test on Monday morning (we're adopting our second child and had to get the test). We had to come in Wednesday morning at 9:45 to see if the injection caused any problems. The NP told us everything was fine and we were TB negative. It's several days later now - Thursday evening - and I'm fine, but my wife has enormous bumps/hives right at the injection site on her arm. I'm assuming the TB test shot is some kind of totally inert drug so you can't actually get sick from it. Why would a disease that we were supposedly negative for cause hives? Is she allergic to something else? Help! Should we just go to the DR now? The hives are pretty weird. Neither of us has any food allergies of any kinds.
posted by luriete to Health & Fitness (22 answers total) 1 user marked this as a favorite
I know advice would be to see MD immediately but as you probably know we can't all afford health care and if we went to the DR now, and waiting in line for 5 hours in the emergency room with my small child (who would probably then get sick from something caught at the hospital), I wouldn't be able to afford the bill. So I was hoping to get a little guidance here as to what we should do first. I assume you can't get really sick from a TB skin test though, right?
posted by luriete at 9:39 PM on January 20, 2011

Also my wife was born in Korea and came here at age 3 but we don't know her early vaccination history if that makes any difference.
posted by luriete at 9:42 PM on January 20, 2011

Has she taken some Benadryl? That might help bring the hives.
posted by bluedaisy at 9:54 PM on January 20, 2011

According to Wikipedia, Bacillus Calmette-Guérin (the tuberculosis vaccine) was given to children in South Korea until 2001, so it is likely that your wife received one. BCG can cause false positives.

PS: Oh ma god, I am SO not a doctor. I have had a positive PPD. It was one itchy, red bump.
posted by i_am_a_fiesta at 9:56 PM on January 20, 2011 [1 favorite]

For what it's worth this site says that hives are the most common side effect of the TB skin test and recommends OTC care. Hives are a pretty typical allergic reaction and they can be pretty gnarly (I've experienced a full-body drug reaction, not pretty). Not sound medical advice but if I were in this position, having read what I just linked online, I'd probably take a benadryl and put some cortisone cream on the hives and give it at least a day provided they weren't getting worse and I wasn't having any trouble breathing. That last one is an emergency room trip obviously, and if they started spreading I'd go straight to the doctor, but if typical allergic reaction response helps it's probably nothing, she's not getting any more of the allergen so it should start clearing up. As to why it didn't show up until several days later, who knows? Who knows why I was able to take amoxycillin half a dozen times without incident and suddenly one day, painful itchy bumps from my collarbones down to my ankles.
posted by nanojath at 10:01 PM on January 20, 2011

Call whoever administered the test. They will be able to tell you what's going on and how to handle it. It looks like your wife isn't the only person to have an allergic reaction to a TB test. It's possible to be allergic to just about anything.

Also, don't panic if it does turn out to be positive! The adoption folks would probably just ask for a chest x-ray to confirm that she doesn't have TB.
posted by corey flood at 10:01 PM on January 20, 2011

Generally with any allergic reaction if it's just a rash, bumps or hives, take some benadryl, see MD tomorrow. If she has trouble breathing or the rash is spreading very quickly, go to the ER.

I would take benadryl now. I would go to a nearby urgent care or to your GP in the morning.

As for allergens, I think there is a chance albumin could be mixed in with the vaccine, however, an actual allergy test would be needed to be conclusive. Same goes for a possible latex allergy (if the NP used latex gloves). Some allergic reactions can take 48-72 hours to manifest, so if it's been three days there is a good chance it is an allergic reaction.

IANAD, but I've had rashes and hives before.
posted by Mister Fabulous at 10:08 PM on January 20, 2011

IANAD, I'm an epidemiologist and this isn't medical advice.

I'm assuming the TB test shot is some kind of totally inert drug

Well, no, not exactly. The Mantoux test uses purified protein from the germ that causes TB to see if you mount an immune reaction (basically a big hive) within 48 to 72 hours of the initial placement. From Monday morning to Thursday night is a late for that, but not so much that I wouldn't give the NP a call tomorrow to decide what to do next. Don't let that alarm you - depending on where and when she was in Korea, she may have had the BCG vaccine, which makes some people yield false positives on the Mantoux test, and since she's outside the positive-reaction timeframe, she's not even technically positive for TB.

Reliable information about the Mantoux test is available from the good old CDC.

I'm betting they'll either advise her to have the test again or they'll just let it stand as a negative. There's a far-out possibility they'll make her have a chest X-ray to be sure.

For now, my lay opinion is that she should go talk to a pharmacist (at Walgreens or any other pharmacy that's night-staffed in the evening), tell them exactly what you've said here, and ask whether it'd be reasonable for her to take an over-the-counter antihistamine like diphenhydramine (that's the common name for Benadryl). Pharmacists know about drug reactions, allergies, and interactions with any medications or supplements your wife might be taking.

In the unlikely event that your wife has trouble breathing, you should call emergency services in your area for guidance. (9-1-1 if you're still in California.)
posted by gingerest at 10:14 PM on January 20, 2011 [1 favorite]

"night-staffed in the evening" "a late" - awesome proofreading, there. (And obviously, the "they" who will make the decision about further testing is your NP, not the CDC.)
posted by gingerest at 10:17 PM on January 20, 2011

gingerest is being very prudent with his or her wording, but in the vast majority of cases, Benadryl is a safe over the counter treatment for itchy rashes including hives. /IANYD

If the hives are all over her body, though, or if she has any other symptoms of a systemic allergic reaction (shortness of breath, lightheadedness, facial/throat swelling etc), a visit to the ER/urgent care visit would probably land her with at the least, a short course of steroids such as Prednisone. Once you get a really generalized itchy rash, Benadryl is not always enough and the steroids can help make the reaction go away. More severe allergic reactions that are not just skin rashes can progress quickly and are nothing to fool around with, they are generally ambulance-worthy.

I recommend looking for a local ER that has an urgent care or walk-in area, if you do decide you need one - at such sites you do not usually have to wait as long (you can call to ensure you go during the right hours for this area to be open), and the cost may be less as well.
posted by treehorn+bunny at 10:26 PM on January 20, 2011 [1 favorite]

thanks everyone!! we will use cream/benadryl tonight and if it's still there in the AM will go see the NP.
posted by luriete at 10:49 PM on January 20, 2011

There is a chance, depending on your location, that they may do a blood test to verify a negative result, given the delayed reaction. It is expensive and not standard (yet) which is why it isn't done routinely, but that seems to be changing, at least in the East Coast immigration centers I've seen.
posted by cobaltnine at 10:58 PM on January 20, 2011

Actually, I've just realized something: If your wife immigrated from Korea, she must have had a PPD done for immigration. You may want to see if you have that paperwork, if appropriate, because a previous positive or negative may affect what they do next.
posted by cobaltnine at 11:00 PM on January 20, 2011 [1 favorite]

Whoops, that last one applies as I read it wrong (if she immigrated three years ago, not 'at age 3'. ) Understandably you don't have those records.
posted by cobaltnine at 11:04 PM on January 20, 2011

I'm assuming the TB test shot is some kind of totally inert drug so you can't actually get sick from it. Why would a disease that we were supposedly negative for cause hives? Is she allergic to something else?

Allergic reactions to the PPD have been described, and it's thought largely to be a response to the preservatives in the formulation (Tween 80, phenol) and not the disease or the bacterial-derived proteins. It sounds like this might be the problem and you've been given fair advice thus far. If a question persists about whether she has possible latent TB, I would bring up the blood test (Quantiferon-TB Gold) as an alternative with her doctor, and probably consider avoiding the PPD in the future. [Usual disclaimer applies: IAAPulmonologist but not yours.]
posted by drpynchon at 3:48 AM on January 21, 2011

IANYD. When I applied for a job in healthcare years ago, I found out that I test false positive for TB. There's a lot of reasons why you might get a false positive: a previous vaccine, or even just previous passing exposure. The Dr wasn't concerned, and just let me know that I'd likely always test false positive and would need to let future doctors and employers know. Talk to your doctor, but I wouldn't freak out too much yet.
posted by ninjakins at 5:37 AM on January 21, 2011

I got the TB vaccine as a child and have been advised to never get the TB skin test - I was told that it would probably generate a false positive due to lingering antibodies from the vaccine. However, according to several public health sites - including this one - that is now considered to be an inaccurate view for people inoculated as children. According to current thinking people who have a positive skin test with no symptoms are most likely carrying an inert form of TB in their system.

Which is all to say you need to contact the PNP and get evaluated by a professional. All the best with your adoption proceedings!
posted by dadici at 8:05 AM on January 21, 2011

The hive was gone this morning.

Weird thing: we had the same test 2.5 years ago when we adopted our daughter, and she didn't get the reaction then.
posted by luriete at 11:31 AM on January 21, 2011

It's not uncommon for allergies to develop after repeated exposures to an antigen.
posted by drpynchon at 4:26 PM on January 21, 2011 [1 favorite]

Well, the hive(s) came back today much worse, redder and bigger, maybe an infection ... she's at the MD now
posted by luriete at 3:44 PM on January 24, 2011

posted by gingerest at 3:21 AM on January 25, 2011

Everything was fine. It was an allergic reaction, but it petered out after a couple of days.
posted by luriete at 11:53 AM on April 8, 2011

« Older [whine filter] How do I deal with burnt bridges...   |   Why are guerrilla tactics so incorrect? Newer »
This thread is closed to new comments.