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Learning About Penicillin Allergy

What is a penicillin allergy?

A penicillin allergy is a bad reaction that your body has to penicillin antibiotics. This is the most common type of drug allergy.

The reaction can range from mild to serious. Common allergic reactions include rashes and swelling. But a severe reaction can cause trouble breathing. This can be deadly if not treated right away.

A severe reaction is more likely if you have had:

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

People who have a penicillin allergy also may react to similar antibiotics. These include ampicillin and amoxicillin. Ask your pharmacist or doctor about these medicines.

A skin test is the best way to find out if you have this allergy.

What are the symptoms?

A mild reaction can cause:

  • A mild rash.
  • Hives.
  • Swelling of your lips, tongue, or face.
  • Itchy eyes.

A severe reaction can cause:

  • Diarrhea, nausea, or vomiting.
  • Dizziness.
  • Trouble breathing.
  • Rapid or weak pulse.
  • Loss of consciousness.

If you have any of these severe symptoms, call 911 or other emergency services right away.

How is it treated?

A mild reaction often can be treated with antihistamines. These medicines stop swelling and itching. They can be bought without a prescription.

Some people may need prescription medicine if over-the-counter medicine doesn't help.

You also can treat a mild reaction by:

  • Taking a cool shower or applying a cool compress.
  • Wearing lightweight clothes that don't bother your skin.
  • Not using strong soaps and detergents. They can make itching worse.

A shot of epinephrine is needed for severe reactions. Sometimes people also get antihistamines and other medicine in a vein.

If you have any reaction to penicillin, let your doctor know right away. Tell other health professionals who treat you that you had a reaction to penicillin.

It's also a good idea to wear medical alert jewellery that lists your allergies.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse call line if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

Where can you learn more?

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