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.
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 75-90% of adults who say they are allergic to a medication
are not. Many patients are 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.
What is “allergy” and are you allergic to that
medication or food?
Allergy is your immune system saying there is a
foreign protein in your body. But it does not know the difference
between a pollen that is nothing, a bacteria that will kill you, or a
heart transplant that will save your life. It will reject them all. So
we all have allergies but to different proteins and to different
degrees.
When you get an infection, many people can have
hives to the germ that is causing it. But when the doctor gives you an
antibiotic and you break out in a rash, you may be reacting to the germ
and not to the medication. Studies show that 90% of patients who say
they are allergic to a medication are not. The skin and blood tests are
only 50% accurate. That is also true of allergy testing for foods.
They are very inaccurate. Many people can take medications and eat
certain foods with no symptoms even though they test positive. The most
accurate way to find out is to have a positive test to both skin and
blood tests and you have symptoms when given that food or medication.
What I recommend: If the child was on an
antibiotic for an infection and breaks out in hives, the medication is stopped,
and 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.
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.
