Penicillin Testing Specialist

Sandra A. Ho, MD -  - Allergy, Asthma, & Immunology Physician

Avant Allergy

Sandra A. Ho, MD

Allergy, Asthma, & Immunology Physician located in Los Angeles, CA

As many as 90% of the 32 million Americans with a recorded penicillin allergy aren’t allergic to penicillin and were misdiagnosed. If hives, rash, or general itching occurs after taking penicillin, you may have a penicillin allergy, but penicillin testing is required to confirm a true allergy. Sandra A. Ho, MD, at Avant Allergy uses penicillin testing for patients in Los Angeles, California, to accurately diagnose a penicillin allergy. If you suspect a penicillin allergy, call or use the convenient online booking tool to make an appointment for penicillin testing today.

Penicillin Testing Q & A

How is a penicillin allergy diagnosed?

Skin tests are the most common method to diagnose penicillin allergies. Dr. Ho places a small amount of penicillin on your skin with a needle. If your skin gets an itchy, raised, red bump, you’re likely allergic to penicillin. 

The testing process takes 2-3 hours. If diagnosed with a penicillin allergy, you may be a candidate for immunotherapy to reduce or eliminate the allergy for future penicillin use.

Why are penicillin allergies misdiagnosed?

Children diagnosed with penicillin allergies due to a rash may be misdiagnosed since viruses treated by penicillin also cause skin rashes. Even children with true penicillin allergies may no longer have the allergy as an adult. 

Some misdiagnosed penicillin allergies are actually intolerances to the medication or penicillin side effects rather than a true allergy. 

What are the symptoms of penicillin allergy?

Penicillin allergy symptoms often occur within an hour after taking the drug, although they can occur hours, days, or even several weeks after taking penicillin.

The most common symptoms of a penicillin allergy include:

  • Skin rash or hives
  • Fever
  • Itching
  • Wheezing
  • Swelling
  • Shortness of breath
  • Itchy, watery eyes
  • Runny nose


Severe penicillin allergies cause anaphylaxis, a life-threatening condition that can lead to coma or death if not treated.

Why is it important to confirm a penicillin allergy?

Many patients experience a mild reaction while on penicillin and then spend their lives avoiding this common, effective antibiotic. Doctors prescribe other broad-spectrum antibiotics if you think you have a penicillin allergy, causing increased health care costs and an increased risk of antibiotic resistance. Broad-spectrum antibiotics affect the good bacteria in your body as well as the harmful bacteria, potentially increasing the risk of infections like MRSA and C. diff. 

The CDC reports that up to 90% of people who believe they have a penicillin allergy aren’t truly allergic, and 80% of those who are allergic lose their sensitivity after 10 years. A simple penicillin test at Avant Allergy determines if you have a true allergy to penicillin. Use the online booking feature or call the practice to schedule an appointment for penicillin testing.