About 10% of individuals report a penicillin allergy, making it one of the most causes of drug allergies. However, it is a crucial first line antibiotic. Researchers report that individuals with penicillin allergies can have a genetic variation on an immune system gene that allows the body to recognize our own cells and harmful bacteria. The HLA gene, which is also responsible for genetic variations that cause adverse reactions to HIV/AIDS medication and gout medication, the the site that was observed to hold the genetic variation in individuals who reported allergies.
A database of 1.12 million people of European ancestry were used to see if the genetic variant can be found in individuals who reported penicillin allergies. Researchers found the same link, however a database of East Asian, Middle Eastern, and African ancestries did not find the same connection. Researchers warn however that many of the penicillin allergies were not confirmed with a test, which is an important distinction because 90% of individuals who report claim to be allergic can still safely take the drug.