Do you Truly Have a Penicillin Allergy?

Penicillin allergy has periodically been on the news- see video below. Penicillin Allergy Day is September 28, which is the day the Sir Sir Alexander Fleming discovered penicillin in 1928. Penicillin antibiotics are safe and effective. These important medications are often not used due to people having a diagnosis of penicillin allergy, and individuals with with penicillin allergy labels are at risk for suboptimal treatment with antibiotics, poorer clinical outcomes, drug-resistant infections, and adverse drug events. While about 10% of the US population (~32 million people) think they have penicillin allergy, more than 90% of those individuals can take penicillins safely. The incorrect labeling of penicillin allergy leads to the use of more expensive, more potent antibiotics. Risk for penicillin allergy can be broken down as follows:

  1. Low risk- those whose reactions have been limited to nausea, vomiting, diarrhea, or itching without rash as well as those who may only have a family history but no personal history of penicillin allergy. In addition, individuals who have a very distant history (over 10 years ago) or have had unknown reactions are also at low risk.
  2. Moderate risk- those who have had hives or other itchy rashes or other features suggestive of an allergic reaction
  3. High risk- those who have had anaphylaxis (life threatening allergic reaction), recurrent reactions to penicillins, positive testing, or multiple allergies to drugs related to penicillins

Evaluation by one of our board certified allergists can help identify people who truly have penicillin allergy. Here at Allergy Asthma Food Allergy Centers, we can help determine whether or not you or a loved one are truly allergic to penicillin through penicillin testing and or office based challenges to penicillin antibiotics. Contact our office to schedule an appointment.

Today Show Penicillin Allergy Story


Updated 9/27/2021

Early Introduction of Peanut

Allergists have suspected for years that early introduction of foods likely decreases the development of food allergies. The LEAP (Learning Early About Peanut Allergy) study published in the New England Journal of Medicine in February 2015, definitively showed that early introduction and regular consumption of peanut (approximately 2 teaspoons of peanut butter 3 days per week) dramatically decreases the risk of developing peanut allergy by about 80%. Since the study was published, new guidelines were also released with the following recommendations:

  1. Children at the highest risk of developing peanut allergythose with severe eczema (atopic dermatitis) and/or egg allergy should have some form of testing to evaluate for the possible presence of peanut allergy. If testing is negative, home introduction or a supervised feeding can be done, and if the child tolerates peanut, they should regularly consume approximately 2 teaspoons of peanut butter at least three days per week. This process should start ideally between 4-6 months of age. If testing is positive, depending on the testing results and the comfort of the specialist, and office based food challenge to peanut may be done to determine if the infant is allergic before introduction at home is considered.
  2. Children in the moderate risk groupthose with mild to moderate eczema and no egg allergy should start consuming peanut (about 2 teaspoons) three days per week starting around 6 months of age. These children do not necessarily need testing before peanut is introduced, which can be done at home.
  3. Children at low risk for peanut allergy- those without signs of eczema and without egg allergy can start consuming peanut when age appropriate and according to family and cultural preferences.

While formal recommendation #3 does not stress early introduction, it is important to note that there is no real downside to early introduction, and delaying introduction even in those without eczema or egg allergy could potentially lead to an increase in developing peanut allergy compared to those who introduce early.

A question parents often have is how peanut can be introduced at home. The video below features Dr. Ruchi Gupta, one of the leading experts in food allergy, discussing home introduction of peanut. We hope you find this helpful!




If your infant or toddler is found to be allergic to peanut, do not despair. There is good recent evidence that early oral immunotherapy (OIT)/desensitization to peanut has very good outcomes (over 90% success rate when done correctly and carefully) and is safe. If you would like more information on OIT, see our Food Allergy Center of St. Louis page.