Penicillin Allergy

What is a Penicillin Allergy?

Penicillin allergy occurs when the body has an abnormal reaction to the penicillin drug, which is often prescribed for the treatment of a variety of bacterial infections. Severe reactions could be dangerous and potentially life-threatening.

A patient will be more likely to develop an allergic reaction to penicillin if they tested positive via a skin test for the allergy, if hives develop quickly after taking the medicine, and if they experienced an anaphylactic reaction to the drug in the past.

What are the Symptoms of a Penicillin Allergy?

The symptoms that are associated with a penicillin allergy could happen within just an hour of taking this medicine. However, allergic reactions can also happen hours, days, or weeks after taking the drug, although that is less common.

Some of the symptoms of penicillin allergy include:

  • Itchy and watery eyes
  • Runny nose
  • Shortness of breath
  • Skin rash
  • Wheezing
  • Swelling
  • Hives
  • Fever
  • Itching
  • Anaphylaxis

Penicillin Allergy Causes

Since it was discovered in 1928, the penicillin family of antibiotics has been a useful antibiotic in treating infections. However, penicillin allergy happens when a person reacts negatively to the medication. The severe reactions experienced are caused by the body’s immune system mistaking penicillin for a harmful substance, essentially fighting it as though it were a virus or bacteria. Some individuals with such an immune response develop antibodies specifically to fight it and are thus permanently sensitive to that form of penicillin. When such a person subsequently comes into contact with penicillin, their body’s immune system continues to attack it, causing the body to release chemicals which are symptomatic of an allergic reaction.

Mild side effects are common and some reactions can even be caused by traces of the drug in food. Over 10% of patients report nausea, diarrhea, rashes, leukopenia (a reduced number of white blood cells), or other negligible symptoms. About one percent of patients experience more serious, but still non-life-threatening problems, including fever, joint pain, hives, irregular breathing, and lightheadedness or fainting. However, a small number of patients — less than five in 10,000 — can experience extremely dangerous reactions, including anaphylaxis, seizures, serum sickness, or heart problems.

How is a Penicillin Allergy Treated?

If you have an allergic reaction to penicillin, you will need to stop taking the medicine and let your doctor know right away so that he or she can confirm what treatment you should pursue. He or she will also recommend another antibiotic remedy that should be safer for you.

Mild reactions can be controlled with antihistamines, or your doctor can prescribe a medication, such as a corticosteroid, if over-the-counter remedies aren’t sufficient.

Epinephrine can be used to treat anaphylaxis, but you will also need to go to the hospital for treatment if this severe reaction occurs.

Penicillin Allergy Prevention

Many do not know they have a penicillin allergy until they have an adverse reaction; therefore, it is difficult to prevent penicillin allergy. However, if you are concerned, allergists can assess patients’ sensitivity to penicillin drugs with a skin-prick test, giving the patient a small amount and monitoring their immune response. This can prevent adverse reactions in future. Patients who are very sensitive to penicillin should discuss this with their doctor and explore whether other antibiotics could be as effective.

If you have a severe penicillin allergy, ensure you make this known when in need of treatment, in order to prevent a reaction. You can do this by requesting it to be added to your medical records, telling healthcare workers, wearing a bracelet which states your allergy, and carrying an emergency epinephrine shot in the event you come into contact with penicillin.

Some doctors estimate that a vast majority of patients alleged to have a penicillin allergy can in fact safely take these drugs if their monitor their symptoms and use a corticosteroid. A recent study by the UK General Practice Research Database looked at over three million patients prescribed penicillin and found that only 0.18% experience true anaphylactic reactions, and only 1.89% of the patients from that group who took penicillin again had a similarly dangerous reaction.

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