Penicillin allergy

Penicillin is the name of the group of antibacterial drugs prescribed for treatment and prophylaxis of various types of infectious diseases (including bacterial endocarditis or rheumatic heart disease).

Penicillin advantage is that they are cheaper than new-generation antibiotics. One of Penicillin disadvantage is that they may cause mild to moderate allergic reactions in some patients.

The risk of allergy to penicillin is observed in patients with a history of atopic allergy, allergic rhinitis, dermatitis, asthma. Hereditary factors do not influence risks of penicillin allergy. Therefore, hypersensitivity to penicillin in the parents does not mean that Penicillin allergy is observed in their children.

Symptoms of penicillin allergy can be classified by several different grounds. If allergy symptoms appear within one hour after the penicillin use, they are called hypersensitivity reactions. Key signs of hypersensitivity include exercise-induced asthma, angiooedema, hives, or anaphylaxis.

If symptoms of penicillin allergy appear within 72 hours after the use of antibiotic, they are called nonimmediate reactions. Delayed allergic reactions occur in three days after intake of Penicillin.

The first signs of Penicillin allergy can be hives, rash, angioedema, itchy eyes and skin, wheezing, or swollen lips. People with hypersensitivity to Penicillin may experience such severe reactions as difficult breathing, low blood pressure, vertigo, or faint. Also nausea, vomiting, slurred speech, blueness of skin, weaker pulse rate, or diarrhoea can be observed.

Symptoms of nonimmediate and delayed reactions may be observed as toxic epidermal necrolysis, exanthematous drug eruption, hemolytic anemia, tubulo-interstitial nephritis, or serum sickness.

Penicillin allergy is often diagnosed by skin testing, consisting of intradermal testing or skin-prick. Skin testing is the most reliable and accurate method for determination of Penicillin allergy. The exact diagnosis of Penicillin allergy is very important, because it helps prevent side effects and avoid serious complications.

Skin-prick means introduction of a small amount of Penicillin and saline onto different skin areas using a thin needle. Redness, itching and burning in a site of Penicillin administration mean positive result of Penicillin allergy test. If the skin is not changed, the result of Penicillin allergy is considered to be negative.

For intradermal testing, a drop of Penicillin and a drop of saline are applied to the skin. Then, small incisions are to be done in the application sites. Results of this method are defined the same way as in the Skin-prick.

Medical examination at Penicillin allergy includes skin testing and chest examination. Maculopapular rash or hives can be observed on the skin. Damaged mucous membrane may indicate toxic epidermal necrolysis. If a patient with Penicillin allergy experiences stridor or bronchospasm, the respiratory system should be examined.

The first stage of treatment of Penicillin allergy is to confirm the diagnosis and to exclude antibiotic, caused allergy. The patient should be injected with epinephrine to prevent fainting. In addition, the patient should wear a special Medic Alert bracelet, indicating the drug /drugs that cause allergy. In case of fainting, the doctor learns about allergy from this bracelet.

Once diagnosed, hypersensitivity to Penicillin is to be reduced. To prevent hypersensitivity to Penicillin, low doses of Penicillin should be periodically administered, being doubled every 15 minutes.  Penicillin administration should be continued till a full dose is achieved.

Most patients with Penicillin allergy may experience adverse reactions to cephalosporins, for example, Cefuroxime, Cefuzonam, Ceftriaxone or Ceftaroline. When using several antibiotics at the same time, cross reactivity is observed. In such a case the skin testing should be done in the patient, and in case of a positive result the patient should switch cephalosporin to another antibiotic.

Penicillin allergy is often observed in children. But skin testing is rarely done in case of rash in children. Many children just get a special penicillin allergic label, wearing it throughout their life.

  • Beta-lactam antibiotics are strictly forbidden in penicillin allergy, such as: Meropenem, Cefuroxime, Cefotaxime, Imipenem, Ceftriaxone, Cefixime, Ertapenem, Ceftazidime, Cefalexin, Doripenem, Aztreonam, Cefradine.
  • Patients with a history of penicillin allergy can be indicated with alternative antibiotics: Oxytetracycline, Erythromycin, Ofloxacin, Doxycycline, Vancomycin, Norfloxacin, Daptomycin, Tobramycin, Amikacin, Linezolid, Sulfadiazine, Teicoplanin, Lymecycline, Ciprofloxacin, Gentamicin, Rifampacin, Azithromycin, Levofloxacin.