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Penicillin allergy is one of the most common allergic reactions to the drug. She can be very strong and can even lead to death at times - fortunately, the latter is relatively rare. Check the symptoms of penicillin allergy.


  • Penicillin allergy: what is penicillin?
  • Penicillin allergy: symptoms
  • Penicillin allergy: adverse reactions to penicillin treatment
  • Penicillin allergy: diagnosis

Penicillin allergymay vary in severity, not always very intense. Until now, scientists have failed to discover why some are allergic to this antibiotic and others are not. It has only been observed that it is not hereditary and that it has no discernible relationship with other allergies.

Penicillin allergy: what is penicillin?

Penicillin was discovered by Alexander Fleming in 1928. It happened by accident. The scientist, arranging the dishes with cultures of bacteria, noticed a growing colony of mold, which was killing the bacteria. He began to do further experiments, and a few years later, together with Howard W alter and Ernest Boris Chain, they isolated the active substance. After a year of further work, they were already producing an antibiotic, for which they were awarded the Nobel Prize in 1945.

Penicillin is the oldest universal antibiotic. It belongs to the family of beta-lactam antibiotics that treat many infections. It works against streptococci, staphylococci, anaerobic cocci, Clostridium difficile and Actinomyces, gram-negative bacteria, spirochetes (Treponema, Borrelia, leptospires), meningococci and many more.

We treat penicillin:

  • angina,
  • otitis media,
  • abscesses,
  • osteomyelitis,
  • sepsis,
  • gonorrhea,
  • pneumococcal pneumonia,
  • menigococcal meningitis,
  • diphtheria,
  • tetanus,
  • syphilis,
  • anthrax.

Penicillins are divided into natural (benzyl penicillin) and semi-synthetic (amoxicillin, phenoxymethylpenicillin, ampicillin, tyracillin, azlocillin, meslocillin, piperacillin, propicillin, carbenicillin, methicillin, oxacillin, clphaxacillin).

It is the natural penicillin that is one of the most sensitizing substances responsible forthe highest number of severe allergic reactions leading to death. In the past, for this reason, before administration of the drug, the so-called penicillin test, today it is used only in inpatient treatment, and whenever possible, patients are given semi-synthetic penicillins. They cause adverse reactions much less frequently.

Things worth remembering:Not all adverse reactions that occur with penicillin administration are allergies. Moreover, not all allergic reactions are equally dangerous. According to recent studies, the number of people allergic to penicillin is overestimated. Only 10% of all people who say they are allergic to penicillin actually have an allergy.

Penicillin allergy: symptoms

Usually allergy to drugs is manifested by skin reactions, and so is penicillin allergy. In her case, these are:

  • hives (approx. 40% of all adverse reactions),
  • rash,
  • erythema covering arms, legs, torso (less often).

However, other systemic symptoms may also occur, such as: laryngeal edema, asthma attack, dyspnoea. In the worst case (approximately 0.01-0.06% of penicillin allergy sufferers), anaphylactic shock occurs, which is life-threatening and requires immediate medical attention. This mostly applies to people aged 20-40.

Shock manifests itself in such a way that within a few minutes of the administration of penicillin the patient begins to complain of malaise, dizziness, drop in blood pressure. There may also appear: reddening of the skin, itching, hives, rapid and shallow breathing, swelling of the face and respiratory tract, which in the worst case may result in suffocation.

Allergic reactions are divided into:

  • immediate - IgE-dependent (up to 1 hour from the action of the allergenic factor),
  • cytotoxic - dependent on IgM, IgG antibodies (symptoms usually after 3 days),
  • immune complexes (symptoms after 3-5 days),
  • delayed - dependent on T cells (symptoms after 7 days).

Penicillin allergy: adverse reactions to penicillin treatment

Undesirable reactions may occur during treatment with penicillin, which, however, must be distinguished from allergies. A rash often appears. In many cases, however, it is not an allergy to the drug, but only a minor side effect that the drug causes, or simply a symptom of the disease itself.

It is also very common that a small child with a "three-day" program, initially manifested by a high fever, goes to a doctor who, unable to diagnose the cause of such a hightemperature, prescribe an antibiotic (just in case). The rash that appears in the following days is not a symptom of an antibiotic allergy, but a confirmation of a three-day period (illegally treated with an antibiotic because it is a viral disease).

Treatment with penicillin can also cause abdominal pain and diarrhea, because - like an antibiotic - penicillin also eliminates pathogenic bacteria, but also the natural bacterial flora of the intestines. In women, it can cause vaginal fungal infections. However, these are not symptoms of drug allergy.

Penicillin allergy: diagnosis

How can I find out if I am allergic to penicillin? Unfortunately, there is no one hundred percent sure method of confirming penicillin allergy. Usually, the blood is tested for the level of penicillin-specific antibodies. For this purpose, they are used:

  • point tests,
  • intradermal tests,
  • patch tests,
  • drug challenge tests,
  • designation of sIgE antibodies,
  • histamine release test from basophils,
  • LTT lymphocyte transformation reaction (in late allergies).

Tests are carried out in allergy clinics specializing in the diagnosis of drug hypersensitivity. The presence of antibodies in the blood confirms an allergy. If no antibodies specific to penicillin are found - it does not mean that there is no allergy (penicillin is broken down in the human body and some people are allergic to its degradation products).

Then a provocation test can be performed - under strict supervision of a doctor in the hospital, the patient is gradually administered increasingly higher doses of penicillin. If symptoms occur, it may be considered an allergy.

It is worth remembering:Once the tests confirm that a person is allergic to penicillin, they will have to reckon with it for the rest of their lives and, if necessary, be treated with other medications. Knowing about an allergy to this antibiotic, you should always tell the doctors about it. For your own safety, you can include information about penicillin allergy in your records or carry a penicillin allergy. dog tag.

Also read

Antibiotics: how do they work and what diseases do they help?

11 tips for choosing a safe antibiotic

Antibiogram before antibiotic treatment: how to read the results?

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