Allergy Chicago,Penicillin Allergy,Rash Identification
I was on a trip in Disney World 8 days after my 5-year-old son had started on Amoxicillin for Strep throat.
I thought to myself, “We are not contagious, and he was feeling great, so let’s enjoy our scheduled trip”! On the last day, he woke up covered in a rash. As the minutes (which felt like hours) progressed, his skin got worse, and the hives looked raised – so I called the pediatrician. I thought – could this be heat rash? An allergic reaction to sunscreen? But we had been there using the same SPF for DAYS. The pediatrician instructed us to stop using the amoxicillin immediately, get some Benadryl in him and to come in the next day. Luckily, he had no evidence of any throat or breathing issues.
When we saw the pediatrician, she told us ‘Kids sometimes develop amoxicillin allergies even if they have been on it before.’ They can also suddenly ‘get allergic’ after being on it for a few days – it didn’t necessarily have to start immediately after the first dose.
The pediatrician told us she would recommend going to an allergist to confirm whether the reaction was due to a true penicillin allergy.
Being the type A mom I am (who is extra careful with school forms) we went ahead and scheduled. The allergist performed an “oral challenge” in the office where they tested my son and it turned out, he was NOT allergic to penicillin. The allergist assured us that this was very normal and that this one ‘reaction’ 6 months ago did not mean my son was allergic to penicillin.
It is important to prevent a lifelong label of being “penicillin allergic.”
There are different reactions to penicillin but with the oral challenge we were able to prove that the risk of having a severe IgE mediated / anaphylactic reaction is minimal. Important to note: the oral challenge doesn’t rule out other autoantibody mediated reaction.
At Majmudar Allergy, we typically do blood work in the office. This tells us if a patient is reacting to the major/minor components of metabolized Penicillin. These are also reactions that happen quickly; and usually, if it is days later, it is not IgE mediated. If a patient tests negative for those with the blood tests, then we know the likelihood of an emergent reaction is extremely low and we would feel comfortable with them doing an oral challenge at home. After both tests, we can officially declare that patient “not allergic”.
So was my son’s reaction ‘a fluke’?
There are other mechanisms that can lead to a rash with penicillin. The most likely being a delayed hypersensitivity reaction. It’s uncomfortable for sure but can be managed with prophylactic antihistamines/steroids if penicillin is for sure the indicated antibiotic. There is also serum sickness (immune mediated complexes).
More than 80-90% of patients who are labeled as ‘allergic to penicillin’ actually outgrow it.
The moral of this story is – if you have never had a severe, anaphylactic reaction to penicillin, and you have been labeled as ‘allergic to penicillin’, go see your allergist and get tested.
Also, if you have a child who has had a reaction to penicillin, amoxicillin or any other medication, and you want a formal diagnosis or ‘closure’ about whether they are truly allergic, please reach out to our office by calling 847-781-3002 or emailing us at info@majmudarallergy.com and come in for an exam to see our specialists today!
