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 www.PediatricInsider.com
Tags: allergy, Benadryl, Claritin, food, hives, reaction, urticaria, Zyrtec
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April 23, 2008 at 1:10 pm
try looking up sulfite allergies. It is in most processed foods, especially snack foods.