Penicillin Allergy

What are the Symptoms of Penicillin Allergy?

Penicillin allergy is a hypersensitivity reaction of the body to the antibiotic penicillin. It is important to note that not all adverse reactions to penicillin are allergic ones, but some may be side effects of the drug. Treatment and prevention of allergic reactions depend upon the type and severity of the reaction.

Common symptoms and signs of penicillin allergy usually develop within a few minutes to an hour after taking the antibiotic. Some of the most common reactions include:

  • Hives
  • Itching, watery eyes
  • Swelling of the lips, tongue, and face
  • Nasal congestion and sneezing
  • Wheezing
  • Difficulty breathing
  • Drop in blood pressure
  • Anaphylaxis (very rare)

If a person believes they are having an allergic reaction to penicillin, they should stop taking the medication and seek medical attention immediately. People who are known to have an allergy to penicillin should avoid taking the drug and inform their healthcare provider.

Diagnosis and Treatment of Penicillin Allergy

The first step in diagnosing a penicillin allergy is for the healthcare provider to take a detailed patient history. The patient should describe the appearance and severity of their reactions. Physical examination is typically done to determine the presence and extent of any skin reactions.

Diagnostic tests can also be done to further confirm a suspected penicillin allergy. The tests may include skin prick tests or a radioallergosorbent (RAST) test. The skin prick test is typically done by injecting a tiny amount of penicillin into the patient’s skin to see if it causes a reaction. If the skin prick test is positive, the healthcare provider may only do a RAST test. The RAST test measures the amount of IgE antibodies in the patient’s blood.

The treatment of penicillin allergy depends on the type and severity of the reaction. For mild skin reactions, medications such as antihistamines or topical creams can be used to relieve the symptoms. For more serious reactions, the patient may require hospitalization for treatment with intravenous corticosteroids and fluids. In some cases, epinephrine is given to reverse anaphylaxis. People who are known to be allergic to penicillin should carry an epinephrine auto-injector (such as an EpiPen) with them at all times.

Prevention of Penicillin Allergy

The best way to prevent penicillin allergy is to avoid taking the drug altogether. People who are known to be allergic to penicillin should inform their healthcare provider of their allergy so that they can be prescribed appropriate alternatives. When necessary, the healthcare provider may choose to pre-treat the patient with antihistamines and/or corticosteroids to reduce the risk of a reaction.