penicillin, what do you think?

Hi all,
   On Sept. 29 Iwas given a ten day course of Augemetin for a sinus issue. Seven days later I broke out in severe hives with angiodema. It took prednisone, zyrtec, and a cortisone shot to get things under control. I don't have hives anymore, but am still a bit itchy. It took a good four weeks to get everyhting under control. I had skin testing done, although my allergist does not skin test for penicillin. I had +4 on my skin testing for everyhting envoronmental except mold and dust mites. I had a rast blood test done for penicillin and it came back negative, although he told me never to take penicillin again. My question is could the rast be wrong? My understanding is the rast doesn't always pick up on drug allergies.

[DrSylvesterMD]

Hi there,
You are right some times this test can show a false negative as it is not so sensitive. Besides since you were put on steroid and anti-histaminic treatment it chances of it being negative is high because these medications bring about immunosuppresion and prevent reaction to allergens.
So I recommend that you do not take Penicillin in the future and instead look for an alternative antibiotic. Always let your physician know that you are allergic to Penicillin.
If you have any further queries do get in touch with me.
Regards,
Dr Sylvester, MD