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Hives.  Urticaria

Hives or Urticaria               

 This is typically an allergic reaction to something that is inside your body.  Topical substances almost never cause hives but instead causes rashes.  Hives are large circular rashes that are larger than pencil eraser size.  If the child has tiny red spots smaller than eraser size and usually 2-3 mm size, then that is a viral rash and not allergic hives.   Some infants with Roseola who have fever and then a few days later get tiny spots on their chest and back get labeled allergic to an antibiotic that was given by their doctor.  The doctor gave an antibiotic for a possible ear infection when the problem was a viral fever.  Then the infant gets labeled allergic when the whole thing was just a common viral illness that every child gets in the first 2 years. 

 There are many causes of hives.  The three most common causes that come to the pediatrician office are listed below.  The others like stress and pollens are seen by the allergist since they persist for long times and more difficult to figure out. 

  1.  Foods.  A person can become allergic to something at any time and it is common to become allergic to eggs or some food/medication at any time.  So you can eat strawberries your whole life and then when 20 yrs old you start having hives from them.  Usually the parent figures this out when the child breaks out multiple times after they give a certain food.  The usual foods are Nuts like almonds, peanut/peanut butter (the peanut is not a nut but a legume from the ground),  seafood, strawberries, and eggs.   But a person can be allergic to anything so it could be their breakfast cereal or anything.  The first thing parents think of are the new foods but it more likely will be the old things that the child has eaten since 6 months old. 

    2.  Medications.  The same applies to meds …. It may be an antibiotic that the child has taken many times and to which they are now allergic.  So it can be after 1 or 9 days of taking the medication.  When stopping the medication the hives should go away in 2 days and if the hives go away a week later then probably not the medication causing it.

    3.  Infections.  Did you know 75% of adults who say they are allergic to a medication are not.  25% are but 75% were mislabeled allergic.  For example I will see a child who had been running fever for a few days at home and the parent was just watching it.  Then the child breaks out in hives all over from the infection and that scares the parent and they bring them in.  Had I seen them in the office during the first day of the fever and given penicillin and broke out in hives a few days later from the infection, then we might have blamed it on the antibiotic.  The more common infection causing it is strep but any germ can do it. 

 So when the child comes in with hives with or without fever and/or cough-cold, I generally stop the allergenic foods and medications, give Benadryl, and give it a week to go away.  If they go away, then the parent restarts one at a time the foods and meds that were stopped.  If the hives continue 10 days or more then go see the allergist for tests. 

 If the child was on an antibiotic for an infection, the medication is stopped, a different antibiotic is given.  The parent is asked to save the first medication and in a few weeks when nothing else is going on , then give 2 more days of  that antibiotic and watch for hives.   Studies show this is safe if the allergic reaction was only hives.  If they break out a second time, then call and we label them allergic to the medication.  Some parents are anxious about giving it again and they want to park outside of an ER or the doctor’s office and give the medication.  Some parents prefer going to the allergist and having them skin tested and that is OK if that is what they are comfortable doing.  I almost never hear from the parents about the child being allergic.

 If they are allergic to peanut butter, nuts or eggs, then we give epipen for the parents or grandparents or school to have on hand in case of allergic reactions.

 Roger Knapp MD
www.rogerknapp.com

 p.s.: Poison ivy is a topical allergic reaction.  The lesions on the skin are NOT contagious.  You cannot spread it around your body or to other people.  We used to think that but doctors tried to experimentally spread it but could not.  It happened that one area broke out in 1 day, another in 3 days and another in 5 days.  We thought it was spreading around from the first lesion. Or the person just got out in more of it.  But the areas are not contagious.  Put hydrocortisone cream on it and if worse, come in for stronger steroid treatments.