Mystery hives

DMT asked, “My daughter is almost 2 and has had several bouts of hives. The first bout or two lasted only a day or two. The third lasted for 8 days, and the fourth for 10 days. They come and go in patches in the matter of an hour or two, and I have been told numerous times that it is a virus. We have been to an allergist, and he does not believe it is due to allergies, either. She has been on Zyrtec for about 1 month. One day, I forgot to give it to her in the am, and she had 2 little hives. Today, she spit the Zyrtec out (and I did not attempt to give her more), and she woke up from her nap with 4 or 5 huge hives. This is leading me to believe it is allergy based. Any ideas?”

This comes up frequently, and I’m glad you asked about it. Many doctors are getting this wrong, and it’s causing more grief for families than the hives themselves.

First: If your child has hives accompanied by difficulty breathing, unconsciousness, or swelling of the lips, throat, or tongue, call emergency services (911) right away. Though most hives are not serious and do not lead to a more severe reaction, you need to react quickly to any reaction that includes difficulty breathing or a loss of consciousness.

Hives (also called “urticaria”) are always raised, always pinkish, and always warm. They come and go quickly—within a few hours, even with no therapy at all, individual hives will fade away, and often will be replaced by new ones. If you circle an individual spot, it will move away or disappear on its own—this is a unique feature of hives, and can be very helpful in making the diagnosis. Hives always itch, at least in children old enough to scratch or tell you that they’re itchy.

In adults, hives are very often triggered by a specific food trigger. This is not the case in children, where mild viral infections cause most hives. Once a child has had hives once, for a little while they’re likely to have recurrences. This is because of the nature of the hives themselves.

Hives are caused by a little explosion of histamine-releasing cells in the skin. The original trigger can be a viral infection, a food, or something physical like pressure or cold. But once the histamine is released, it recruits and pulls in more cells that are primed and ready to release more histamine—causing more hives!

Usually the infectious trigger can’t be diagnosed without extensive testing for viruses, which is not typically done. One infection that should be considered is strep throat, which should be treated with antibiotics if tested positive. (Strep throat should never be treated without first doing a confirmatory test. Doctors are not good at diagnosing strep by eye, no matter what we say.)

When your child has hives, your doctor should review the history to see if there are any food exposures. Though these are less common triggers than mild infections, if a suggestive food has been consumed shortly before the hives (peanuts, tree nuts, milk, dairy, berries, seafood, egg) then keep that in mind for potential testing or rechallenging later. Certainly if hives are recurrent, it makes sense to very carefully consider the food, medication, and environmental history to see if there is a common exposure. Usually, in children, there is no identifiable trigger; but when there is the parents usually figure it out themselves. Allergy tests are over limited value, as false positive and negative tests are common when trying to find the cause of hives. When there is no specific food trigger, recurrent hives are called “idiopathic urticaria.” (This is the most likely diagnosis in DMT’s daughter.)

If hives are recurrent, the best strategy is to suppress the histamine action with regular use of an antihistamine medication. Zyrtec is a good choice, as is Claritin; older medicines like Benadryl work well but can be sedating and have to be taken more frequently. Work with your doctor for the exact dose and schedule, but it will be important to take the antihistamine regularly for several weeks or more, to suppress the histamine reaction and prevent a snowballing effect of worsening hives.

If hives recur despite continuous use of antihistamines, the next step may be to add other medications (including perhaps Singulair and/or Zantac, which can be helpful but are not FDA approved for this purpose.) Best of luck!

© 2008 Roy Benaroch, MD from

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17 Comments on “Mystery hives”

  1. Rhonda Says:

    try looking up sulfite allergies. It is in most processed foods, especially snack foods.


  2. I have been writing a blog chronicling my journey with chronic hives, I am sharing all that I am trying – if you would like to read and see what I try out, check it out at


  3. […] Mystery hives « The Pediatric InsiderApr 14, 2008 … Doctors are not good at diagnosing strep by eye, no matter what we say.) When your child has hives, your doctor should review the history to … […]


  4. […] Mystery hives « The Pediatric InsiderApr 14, 2008 … When there is no specific food trigger, recurrent hives are called “idiopathic urticaria.” (This is the most likely diagnosis in DMT’s daughter.) … […]


  5. Penny Anastasi Says:

    My son, now 2 has had 4 bouts of hives when a virus becomes an infection. He is in daycare and always seems to have a runny nose ( as all the kids do). The Zyrtec and Benedryl don’t seem to get rid of them. Steroids do, but my husband and I are so upset when he has to be on it. When will this end, will he grow out if it?


  6. Dr. Roy Says:

    Idiopathic urticaria usually improves with time, but no one can predict exactly when your son will grow out of it.

    Why are you so upset about taking antihistamines? Many people take these medications every day, safely, for hay fever and allergies.


  7. Penny Anastasi Says:

    The Steroids is what we don’t like giving him frequently. Our Pediatrician just lowered the amount of days he would be in it, if it happens again.


  8. Dr. Roy Says:

    Ah, that makes sense. Long-term or frequent use of oral steroids (unlike antihistamines) can have lasting and serious effects. Steroids should typically have a very limited role in the treatment of hives, especially recurrent hives. You may wish to ask for a referral to an allergist for further eval and management.


  9. Penny Anastasi Says:

    We have been to an Allergist. No known allergies so far, bloodwork all normal.


  10. Stephanie Says:

    Dr. Roy – RE: the longer term use of a product like Claritin, how safe is it to be taking these products daily (1X/day) for several weeks or more? (assuming the child is over age 3)


  11. Dr. Roy Says:

    Stephanie, when Claritin was FDA approved as a prescription, it was approved for long-term use, with no restrictions. There are no clinical data showing long term problems with oral antihistamines like Claritin, nor is there any physiologic reason to suspect that long term use could become harmful.


  12. loratadine Says:

    loratadine is a major affect on patient well-being. I should certainly have been better specific for adult men and women they shouldn’t end up surprising that
    the CLARITIN may badly affect the decrease urinary tract.


  13. Carolyn Says:

    Thanks so much. My 3 year old has had post viral hives for about 4 weeks. They come and go and get worse over the course of the day. It is really freaking the preschool teachers out…and probably some of the parents. We are going to try to add zyrtec to the attack plan. He seems to not be bothered at all by “his bumps” but I’m just trying to understand it better to make it not seem so scary to others.


  14. Jamie Says:

    My 19 month old son got hives about 3 weeks ago. After a week I took him to the doctor & I was told that it was more than likely from a virus. The hives come on quickly and seem to fade and go away in a fairly short amount of time. And they don’t seem to faze him much – just occasionally might be itchy. But, now he is still getting them about every other day. We have only been giving him Zyrtec and/or Benadryl when he gets the hives.
    Questions: Should we be giving him the Zyrtec daily? And if so, for how long? If the hives are from a virus – shouldn’t they go away once he feels better?
    This article has been very helpful!
    Thank you!!!


  15. Dr. Roy Says:

    Jamie, the virus may be gone, but the mis-guided antobodies lurk around for a while. It’s best to use an antihistamine daily, every day, until the hives are gone and don’t reappear. Otherwise you’re kind of chasing your tail. Ask your own doc for specific advice on exactly how long, doses, etc.


  16. Jessica Says:

    My 18-month-old son has had 4 cases of hives and every time was because of a cold. When he develops hives, a day or two later his cold symptoms show up. Is it possible that there is something wrong with his immune system, it’s confusing the virus and attacking his own body causing the hives?


  17. becky Says:

    All my kids have had hives reactions. As long as it doesn’t affect their breathing, just give them some Benadryl and they’ll be fine.


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