Why Should You Be Tested for Penicillin Allergy?

• Studies have shown that more than 90% of patients who think they are allergic to penicillin are actually not allergic to it!
• Being labeled with a penicillin allergy can have detrimental effects on your healthcare as you may be prescribed second-line antibiotics when penicillin would be preferable.
• Penicillin skin testing and an amoxicillin oral challenge will help clarify whether or not you are actually allergic.
• Penicillin and related drugs (Amoxicillin and Augmentin) are commonly used drugs to treat ear infections, sinus infections, skin infections and other infections. Penicillin based drugs are also a common allergy.

What to expect?

• Both the skin testing and oral challenge are performed in our clinic.
• Please plan for the penicillin skin testing to take approximately 45 minutes. If the skin testing is negative then we will schedule an oral challenge, which takes approximately 75 minutes. If you have a reaction, you may need to be monitored for longer.
• Prior to either procedure, please stop antihistamines (Benadryl, Claritin, Allegra, Zyrtec, etc) at least 5 days in advance
• During the skin testing, you will first have skin prick testing. Skin prick testing involves applying a small drop of the test material (in this case, it will be penicillin, a penicillin derivative, and a positive and negative control) and scratching your skin. We wait for 15 minutes after the scratch and monitor for a local skin reaction.
• If you do not have a reaction, then the second step of skin testing is intradermal testing. We will inject a small amount of the test material under your skin and again monitor you for 15 minutes.
• If your skin testing is negative, then we will perform a graded oral challenge. We will first give you a small dose of amoxicillin orally and monitor you. If you do not have a reaction, then we will give you a higher dose until you reach a dose of 500mg.
• You will be monitored closely throughout the challenge. We will frequently check on your symptoms and vitals signs
• If you have a reaction, we will treat your symptoms. A challenge is concluded if you have symptoms as a reaction confirms a diagnosis of penicillin allergy. If you tolerate the final dose of amoxicillin, then you are not to be allergic to penicillin at this time.

 What are the benefits?

The benefit of penicillin skin testing and an oral challenge to amoxicillin is to clarify your allergy status to this class of medications. These medications are commonly prescribed and are often the first-line medications, meaning they are the first choice for an infection.

What are the risks?

The main risk of skin testing will be local skin irritation. If you are allergic to penicillin, you will have a local skin reaction, similar to a hive. With the intradermal step, there is also a small risk of bleeding and infection. Rarely, patients can have more significant reactions to skin testing, but this is unusual. The main risk of the oral challenge is an allergic reaction, which can range from mild to severe and life-threatening. Symptoms of an allergic reaction can include itching, hives, trouble breathing, nausea/ vomiting and lightheadedness/ low blood pressure. If your skin testing is negative, the risks of an oral challenge are much lower, which is why we always start with skin testing. This testing only answers the question of whether you have an immediate type allergy to penicillin; it does not predict delayed type reactions, such as delayed rashes.