Question:
Today I called a doctor's office and spoke to a nurse, trying to
schedule an appointment for an allergy test to penicillin. She told me
that the doctor refuses to test for this since it is not accurate. She
also said that I will have a hard time finding a doctor who will test.
Is this common, and can anyone tell me why doctors refuse to test? I
had been treated for Lyme Disease, and there is a possibility that I
still have it. I'm in my late 30s, and I would very much like to have
a second child as soon as possible. My Lyme doctor said that the only
safe antibiotic to take while pregnant will be forms of penicillin. I
have never had a reaction to this until last year. I had oral surgery,
took amoxicillin and, within a week, discovered a rash. I hadn't known
that I had Lyme at the time, and wonder if this rash could have been
due to this instead. The Lyme doctor suggested that I get tested.
Answer:
Testing for Penicillin allergy is not a simple matter like testing for
ragweed or house dust allergy. There are many different breakdown
products as well as the penicillin itself that people are allergic to.
These are not commercially available yet, although they are in testing
at major medical centers and some allergists have access to them.
The bottom line is that a NEGATIVE test might NOT mean that you are ok
to take pen and not allergic.
A POSITIVE test definitely says that you are allergic, however.
Two other thoughts: 1. amoxicillin gives a tiny pinpoint rash that
is not believed to be an allergic reaction. 2. If you have a
complete treatment course for Lyme the CDC would say that you have
been treated for the infection and repeat courses of antibiotics for
that infection are NOT indicated. May be another cause for any on
going symptoms needs to be sought or the symptoms are due to
immunological aspects of the disease and not the persistence of
infection. (yes - I expect objections form the LD crowd)
Allergy skin tests for penicillin may not be accurate, but there is a
test called the oral challenge that is. It is preceded by skin tests; if
a reaction happens there, the oral challenge is not attempted. But if
there is no response, you can be given incremental doses of the drug you
might be allergic to, and you will be watched to see if you respond.
From what I know, having been through all this, any life threatening
reaction will occur almost immediately; if you can get through the
challenge and take one full dose of the medication, you will probably be
fine in taking it, even if you do get a rash along the way.
This must be done by a competent allergist.
If you are allergic, you may be able to be desensitized to the drug.
Depends on what kind of allergic rx you have. Once desensitized, you
will be able to take the drug for any length of time, as long as you
don't go off it; a break of as much as 24 hours may make you lose the
desensitization. So if you are vomiting from morning sickness, this
could be a problem.
In any case, your doctor is not correct about nobody doing testing for
this. It is done, and fairly frequently, although usually in a pediatric
setting.
If you are in the NY area, I can even recommend some very good allergists
who do this sort of thing.
The most important thing is to get a doctor who will believe in treating
you through a pregnancy. Forget about what the CDC will or will not say
about further treatment. their criteria is really only supposed to be
for reporting purposes and tracking of the disease. As far as I know, it
is exceeding their authority to make treatment recommendations; that is
between you and your doctor.
