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Penicillin, the first antibiotic ever discovered, is a lifesaving drug, but many Americans report they’re allergic to it. You might not realize that this allergy can be outgrown, or that there are different types of reactions to medication. Thankfully, there is a way to test for penicillin allergy that can open up antibiotic options and avoid higher-priced, more risky alternative medicines.


The Difference Between Side Effects And An Allergic Reaction

Reactions to medications differ, with true allergic reactions being in the minority. But people can experience side effects when taking penicillin. These include:

  1. Upset stomach
  2. Headache
  3. Tongue pain
  4. Delayed rash several days after starting the medication


A true, life-threatening drug reaction has different symptoms that may happen immediately or on the same day. These include:

  1. Itching
  2. Hives
  3. Swollen lips, tongue or face
  4. Shortness of breath
  5. Wheezing


The incidence rate of those who have a severe allergic reaction that is life-threatening is rare, between one and four per 10,000 doses. If you experience a serious reaction, call 911 and seek immediate medical attention.


If you’ve had reactions to penicillin, an allergist can take a proper history, decide which reaction was most likely and give further guidance on how to proceed. Penicillin allergy testing has been extensively studied and standardized, and is available at some allergist offices.

If you think you might be allergic to penicillin, get evaluated by an allergist who will test you, if appropriate, and give further guidance.

Weekly Health Tips are brought to you by UCF Health, the College of Medicine’s physician practice. Offering primary and specialty care under one roof, UCF Health treats patients age 16 and up in primary care and age 18 and up for specialty care. Most major insurance plans are accepted. Two locations are now open: the original in East Orlando at Quadrangle and University boulevards just blocks from the main UCF campus, and the newest one in Medical City at Narcoossee Road and Tavistock Lakes Boulevard. Information for both facilities can be found at, or call (407) 266-DOCS to schedule an appointment.

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