Can a penicillin allergy skin test show up negative but you still be allergic?

Question

I went in for a penicillin allergy testing and the skin test showed up negative so they had me take a pill and I had hives, swollen tongue, and I puked (I’m pregnant too tho). But they said that the skin test is always accurate and taking a pill is more of a comfort thing and passed me anyway.

Answer

You can have allergies that vary. Some people are only allergic topically, if ingested, etc. 
There are even some weirder ones, where you may be only allergic to something before the protein is broken down by  cooking/heating!! 
For example, I’m allergic to cantaloupe period. Can’t touch or eat it. 
However, I’m only allergic to raw blueberries! I can eat them if they’ve been thoroughly cooked, and nothing happens if I just touch them. 
I’m only allergic to cinnamon topically. I can eat it, but I get massive hives if it’s on my skin.

Can a penicillin allergy skin test show up negative but you still be allergic?

The Top Baby Tracker App: Embrace New Beginnings with Tender Care

The Top Fertility Tracker App: Your Path to Achieving Pregnancy

The Top Pregnancy App: Nurturing Your Journey to Motherhood

The Top Period Tracker for Empowering Your Menstrual Health Journey