What is penicillin allergy?

What are the symptoms of a penicillin allergy?

A mild reaction can cause a rash, a few hives, and itching. A severe reaction can also include swelling, dizziness, trouble breathing, passing out, or vomiting. These severe symptoms may be signs of anaphylaxis and must be treated right away. Call 911. These symptoms most often happen very soon after you take the medicine.

How is an allergic reaction to penicillin treated?

The first thing to do to treat a penicillin allergy is stop taking the medicine. A mild reaction often can be treated with over-the-counter antihistamines. These medicines stop swelling and itching. Some people may need prescription medicine. For a severe reaction, you may need a shot of epinephrine or other medicines.

How is a penicillin allergy diagnosed?

To find out if you have a penicillin allergy, your doctor will ask about your symptoms, such as:

  • What they were and how bad they were.
  • How soon they happened after you took the medicine.
  • How long ago they happened.
  • How they were treated.

You may get a skin test to check your reaction to penicillin. Your doctor may give you small doses by mouth. An allergic reaction most often happens quickly. You'll be watched closely while you have the test.

If the test is negative, then you are not allergic to the drug. You may never have been allergic. You may have had side effects instead of an allergic reaction. Or you may have lost the allergy over time.

How can you care for yourself when you have a penicillin allergy?

Avoid penicillin and medicines like it. Be sure that anyone treating you for any health problem knows what medicines you are allergic to. Take medicines for the allergic reaction as directed. If you are at risk for a severe allergic reaction, always have an epinephrine shot with you. Make sure it has not expired.

Penicillin allergy: Overview

A penicillin allergy means that the body's immune system overreacts to something in the drug. This triggers an allergic reaction.

Symptoms of an allergic reaction to penicillin include itching and hives. You may wheeze and have trouble breathing. Your face or lips may swell, and your throat may feel swollen or tight. These symptoms most often happen very soon after you take the medicine. Sometimes, though, an allergic reaction happens later. You could have a rash or other symptoms.

A side effect is a symptom that is caused by the way a drug works or by some ingredient in the drug. All drugs can cause side effects.

Side effects of penicillin include nausea and diarrhea. Others are headaches and yeast infections.

Many people who believe they have an allergy to penicillin don't have it. They may have a side effect instead. Tests can show if you have a penicillin allergy.

What increases your risk of a severe allergic reaction to penicillin?

Severe allergic reactions to penicillin can be deadly. You may be more likely to have this type of reaction if you have had:

  • A positive skin test for a penicillin allergy.
  • Hives that appeared quickly after you took the penicillin.
  • A bad reaction to penicillin in the past.

You are not likely to have an anaphylactic reaction to penicillin if you have had a rash with red, blotchy spots that appeared from a few hours to days after you took penicillin.

What is a penicillin allergy?

A penicillin allergy is an allergic reaction that your body has to these antibiotics. It can range from mild to severe. Common reactions include rashes and swelling. But a severe reaction can cause trouble breathing or other serious problems. This can be deadly if not treated right away.

If you are allergic to penicillin, you may also react to antibiotics like it. These include ampicillin and amoxicillin. Ask your pharmacist or doctor about these medicines.

Many people who think that they have an allergy to penicillin don't have it. They may have a side effect instead. Tests can show if you have an allergy or a side effect.

You're more likely to have a true penicillin allergy if you've had:

  • Hives or swelling that appeared right after you took the medicine.
  • A severe reaction to penicillin in the past.
  • A positive skin test for penicillin allergy.

Why is it important to know if you have a penicillin allergy?

Sometimes penicillin is the best medicine to treat your illness. Knowing for sure if you have a penicillin allergy will help you get the best treatment and avoid problems.

If you really are allergic to penicillin, then you may get other antibiotics instead. Some of these drugs kill a broad range of bacteria, including "good" bacteria. The drug you get may not treat your illness as well. Or it may lead to health problems. It may also cost more.

Taking an antibiotic that isn't the best one for you can cause another problem. It's called antibiotic resistance. This can make it harder to treat infections. It happens when some bacteria aren't killed by the medicine. They live, and this leads to more bacteria that the drug can't kill. This can cause infections that drugs can't cure.

After you find out if you're allergic to penicillin, make sure your medical record is correct.

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The content above contains general health information provided by Healthwise, Incorporated, and reviewed by its medical experts. This content should not replace the advice of your healthcare provider. Not all treatments or services described are offered as services by us. For recommended treatments, please consult your healthcare provider.