Penicillin Allergy

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Penicillins belong to a class of antibiotics named Beta-lactams, which play a vital role in treating bacterial infections ranging from a throat infection to a sinus infection. Common penicillin includes ampicillin, amoxicillin, and augmentin.  What is Penicillin Allergy? Penicillin allergy is the allergic reaction produced by a person’s immune system when exposed to penicillin medication. It is […] Read More

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Penicillin Allergy

Penicillins belong to a class of antibiotics named Beta-lactams, which play a vital role in treating bacterial infections ranging from a throat infection to a sinus infection. Common penicillin includes ampicillin, amoxicillin, and augmentin. 

Penicillin Allergy
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What is Penicillin Allergy?

Penicillin allergy is the allergic reaction produced by a person’s immune system when exposed to penicillin medication. It is the allergic reaction produced when the immune system overreacts to penicillin antibiotics.

It is pretty common amongst children but has a 90% tendency to stop as they grow into teenagers. Only about 20% of people with documented cases of penicillin allergies are still allergic after 10years of initiating the occurrence. 

Research has shown that 10% of people with allergic reactions could be attributed to penicillin allergy. They are the most common cause of drug allergies. However, most people think they are allergic to penicillin and have no tolerance for penicillin, which implies that 9 out of 10 persons with complaints of penicillin allergy are just avoiding it for no reason and penicillin serves as an effective treatment for many infections.

Penicillin allergy
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Causes

Penicillin allergy is caused by the hypersensitivity of your immune system to penicillin, recognizing it as a harmful substance, as a result producing antibodies that react with the penicillin in your body leading to allergic reactions.

Risk Factors 

  • The most common risk factors for penicillin allergy are listed below: A previous reaction to penicillin antibiotics
  • Family history of penicillin allergy
  • High doses of penicillin therapy, increased exposure to penicillin, long-term usage of the drug.
  • Persons with HIV 
  • Persons with Epstein-Barr 
  • Hay fever

Complications of Penicillin Allergy

Penicillin allergy could lead to complications such as:

  • Serum sickness is characterized by fever, rash, joint pain, swelling, and vomiting.
  • Headaches 
  • Vaginal itching
  • Drug-induced anemia is due to a reduction in red blood cells in the body. This could produce tiredness, dizziness, shortness of breath, and other symptoms.
  • Drug reaction with eosinophilia and systemic symptoms(DRESS) could affect the lymph nodes, causing them to become inflamed.
  • Stevens-Johnson syndrome or toxic epidermal necrolysis results in a severe and painful rash that blisters and sheds.
  • Nephritis or inflammation of the nephron in the kidney results in urine and swelling all over the body.

Symptoms

Most allergic reactions to penicillin occur very quickly. Sometimes, in less than an hour after its administration.  

Symptoms could include:

  • Hives also called itchy rash
  • Angioedema or swellings around the face, mouth, feet, and hands
  • Itchy eyes
  • Tight throat
  • Coughing
  • Runny nose

In severe cases, anaphylaxis may occur. Anaphylaxis is a severe condition characterized by:

  • Swelling of the tongue, throat, and lips.
  • Respiratory distress such as difficulty breathing, nasal congestion, chest tightness, wheezing
  • The cardiovascular effect such as decreased blood pressure, dizziness, irregular heartbeat, weak pulse
  • Skin turning blue,
  • The gastrointestinal effect such as nausea, abdominal cramping, vomiting, diarrhea,
  • Loss of consciousness.
  • Brain seizures

Penicillin Allergy Test & Diagnosis

In the diagnosis of penicillin allergy, the following are done:

  • Physical Examination 

You might be asked some questions such as:

What medications did you take? When did you take it? When did the reaction happen?

What kind of reaction happened?

How long did the reaction last?

  • Skin Test

This test includes pricking the skin with the drug penicillin. A subsequent reaction in the form of a red rash and itchy around the area indicates positive penicillin allergy. If the result is negative, oral penicillin is administered, and you will closely observe for some time.

  • Intradermal Test

This involves placing a small amount of penicillin under the skin and placed under close observation.

  • Challenge Test (in the absence of a skin test). 

This procedure involves administering penicillin with a small dose and waiting for 30min to see if there is any reaction. If there is no reaction, the dosage is increased and will be checked after 30-60minmins for any reactions.  

This process continues about 3-4 times until a full dose is administered. If there are no symptoms, then there is no allergy. It is also called desensitization.

Treatment of Penicillin Allergy

 Treatment for penicillin allergy include:

  • Administering epinephrine shots intravenously to help maintain blood pressure
  •  Antihistamines such as diphenhydramine and corticosteroids can be administered. 
  •  Administering alternative antibiotics. 
  • Desensitization involves administering penicillin in 15-20min intervals, starting with a small dosage and progressively increasing. Desensitization is done when penicillin is the only drug of choice for a particular infection.
  • In critical cases (large overdose), hemodialysis is done for amoxicillin, ampicillin, and ticarcillin drugs.

Prevention and Recovery of Penicillin Allergy

You can prevent penicillin-allergic reactions by avoiding drugs that belong to the penicillin family, such as amoxicillin, ampicillin, amoxicillin-clavulanate, dicloxacillin nafcillin, cephalosporin class also.

Recovery 

The recovery period of penicillin allergy will take a few days to weeks, based on the patient’s condition. If the allergic reaction occurs during childhood, there is no need to be alarmed as only 20 percent of people will be allergic to penicillin reaction after 10years from their initial allergic reaction if they are not exposed to it again during that time.

FAQ

  • Is penicillin allergy genetic?

Research is still ongoing, although there has been no predictable pattern to genetics or inheritance of penicillin allergy.

  • What are the alternate antibiotics I can take instead of penicillin if I have a penicillin allergy?

 You can take alternative antibiotics like tetracyclines, quinolones, macrolides, aminoglycosides, glycopeptides, etc. [1].

  • What does penicillin rash look like?

Penicillin rash is characterized by a flat red patch on the skin. It could be described as a maculopapular rash. This kind often develops 3 to 10 days after starting the drug.

  • What happens if I take amoxicillin and I am allergic to penicillin?

Amoxicillin belongs to a class of penicillin class of antibiotics and could cause an allergic reaction if you are allergic to penicillin; hence has to be avoided.

  • Can I take augmentin if I am allergic to penicillin?

If you have a penicillin reaction, you are more likely to have an allergic reaction since augmentin belongs to the penicillin class.

References:

  1. Guidance on Antibiotic Choice for Patients with Penicillin Hypersensitivity