Penicillin Allergic Reaction: Causes, Symptoms Treatment

Penicillin Allergic Reaction: Causes, Symptoms and Treatment

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Drugs and antibiotics like Penicillin are known to induce allergic reactions and hypersensitivity reactions in many people. But why does it occur and what are it’s symptoms and treatment?

Penicillin allergies have been over reported all across the globe as drug allergy due to penicillin is the most common allergy prevalent worldwide. Penicillin allergy is characterized by some peculiar signs and symptoms such as hives, rash, itching, nausea and so on. Some people who are allergic to penicillin are also allergic to other closely related antibiotics, including cephalosporins, such as cefprozil, cefuroxime, and cephalexin.

In today’s article in sound health solution, we’ll briefly talk about penicillin-induced allergic reactions, it’s causes, symptoms, and treatment. Let’s begin!

For more details, you can also read our blog on soundhealthsolution.comPenicillin Allergic Reaction: Symptoms, Diagnosis & Treatment

So what is Penicillin Allergy?

Penicillin-allergic reaction is a type of drug allergy caused in response to our immune system. Our immune system recognizes the drug as foreign bodies and triggers reactions. Penicillin is one of the most commonly prescribed antibiotics that belong to the group of antibiotics, beta-lactams. Penicillin is used to treat several bacterial infections since the early 40s. But after the overuse of the drug, many started having an allergic reaction to it.

Are you using your antibiotics in the right way? Learn more about through the article Antibiotics & Its Appropriate Use | Use Of Antibiotic Medicines

Penicillin Allergy: Symptoms

Penicillin-allergic symptoms start to occur within an hour after the consumption of the drug. Some of the common signs and symptoms of the allergy include:

  • Rashes on skin
  • Hives
  • Itchy skin
  • Fever and swelling
  • Shortness of breath
  • Runny nose
  • Watery eyes

Under severe allergic reaction, anaphylaxis might occur. Anaphylaxis is a serious allergic reaction that is rapid and can even lead to death. Some signs and symptoms of anaphylaxis include:

  • Nausea and abdominal cramps
  • Drop in blood pressure
  • Seizures
  • Unconsciousness
  • Dizziness
  • Vomiting and diarrhea
  • Choking
  • Difficulty in breathing

If you or someone in front of you are having an anaphylactic attack, call 911 for emergency and if available, inject epinephrine in your thigh muscle.

Who are at the risk of Penicillin Allergy?

Penicillin allergy can occur to anyone but you might be at the higher risk of this allergy if you have:

  • other drug allergies
  • Family who have the history of allergy
  • other allergies like hay fever
  • Epstein-Barr, Type of herpes virus

Penicillin hypersensitivity is unpredictable as an individual who previously had no reaction or allergy may show allergy on the subsequent administration of the antibiotic. Penicillin G is the most common drug implicated in drug allergy. Penicillin-allergic reaction is an immune-related hypersensitivity disorder. The mechanism of this hypersensitivity follows the antibody/antigen reaction.

Diagnosis of Penicillin Hypersensitivity

If you are having any kind of allergic reaction after consuming penicillin, then you can confirm whether you’re allergic to the drug through some tests. One of the most common diagnostic tool for penicillin sensitivity test is the skin test.

  • Skin Test– This test is simple and effective. In this method, the doctor uses a tiny needle to prick your forearm and give you a weak dose of penicillin. If you are susceptible to the allergy, your skin will get an itchy bump in about 15 minutes, if not, then she’ll give you a moderate dose of penicillin under the skin of your forearm. Again, if you donot get a bump within 15 minutes, you’re not allergic, but if you do, then you are allergic to penicillin.
  • Challenge TestMost of the time, you get a challenge test when you really need penicillin and your doctor doesn’t have a skin test. For the challenge test, she will start you with a small dose. If you don’t have a reaction after 30 to 60 minutes, you’ll take a higher dose. You will work your way higher every 30 to 60 minutes until you take a full dose. It usually takes four to five doses.  If you don’t have symptoms after the full dose, you don’t have the allergy.

Also Read:Antibiotic & Antimicrobial Resistance, Side Effect, Allergy

Penicillin Allergy: Treatment

Treatment of penicillin-allergic reaction can be divided into two strategies:-

  1. Treatment of the allergic symptoms
  2. Desensitization to penicillin

1. Treatment of the allergic symptoms includes:-

Withdrawal of drug

If you experience any symptoms causing discomfort to you after the use of penicillin, stop the use of the drug immediately and contact your doctor.


Available over the counter antihistamines can be used to reduce the allergic symptoms. This blocks the chemical mediators of the immune systems, histamine. Do not forget to contact your doctor even if you are free of allergic symptoms.


Serious penicillin allergic reaction warrants for the use of corticosteroids (oral or intravenous).

Treatment of Anaphylaxis

Anaphylaxis is a serious medical condition and needs urgent medical attention without which people may die. Treatment of anaphylaxis includes maintenance of airway, breathing, and circulation.

  1. Prompt maintenance of the airway and breathing is needed. The patient may need endotracheal intubation.
  2. Circulation is maintained by gaining intravenous access and infusion of large amounts of fluid. Intravenous epinephrine and intravenous corticosteroids should be given immediately after intravenous access.

So are there any penicillin allergy alternative antibiotics?

The answer is affirmative. Penicillin allergy occurs when a person’s immune system produces antibodies against the antibiotic. Hence, if you have to take an antibiotic just like penicillin, but you are allergic to it, then your doctor will prescribe you alternative antibiotic. Some of them include macrolides(such as clarithromycin, azithromycin, fidaxomicin, telithromycin), some newer cephalosporins, carbapenems( such as iminepem-cilastin) and so on. However, it’s important to talk with your doctor before taking up any other antibiotics if you have a penicllin allergy.

Related Articles:

Antibiotic & Antimicrobial Resistance, Side Effect, Allergy

5 Food Allergies That You Should Not Ignore

Gluten And Its Effects On Human Health | Gluten Sensitivity & Allergy

Allergic Reaction: Types, Symptoms, Prevention & Treatment


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