What is the diagnosis and treatment for Penicillin (antibiotic) sensitization?

From the Guidelines

Patients with a reported penicillin allergy should undergo evaluation to delabel the allergy if appropriate, as approximately 90% of these individuals are not truly allergic and may be unnecessarily treated with less effective, more toxic, or more expensive antibiotics. This is based on the most recent and highest quality study available, which provides a strong recommendation with moderate certainty of evidence 1. The burden of a penicillin allergy label can lead to suboptimal medical care, increased costs, and a higher risk of developing antibiotic-resistant infections or surgical site infections.

Key Points to Consider

• Approximately 10% of patients report a history of reacting to a penicillin class antibiotic, but when evaluated, 90% of these individuals tolerate penicillins and are labeled allergic unnecessarily 1.
• The penicillin allergy mislabel is not benign and can lead to the use of broader-spectrum antibiotics, which may be less effective, more toxic, or more expensive 1.
• Evaluation and potential delabeling of penicillin allergy can lead to improved antibiotic selection, decreased use of broad-spectrum antibiotics, and cost savings 1.
• Patients who may benefit from rapid and acute assessments include those prior to surgery, transplant, or chemotherapy; those on second-line, less preferred antibiotics; or pregnant women prior to delivery 1.

Recommendations for Clinical Practice

• A proactive effort should be made to delabel penicillin allergy whenever possible, and strong efforts should be made to educate patients and clinicians about the benefits of delabeling 1.
• Evaluations are ideally performed electively, when patients are well and not in immediate need of antibiotic treatment, but specific patients may benefit from rapid and acute assessments 1.
• Formal allergy testing through skin testing and potentially an oral challenge in a controlled medical setting can help clarify a patient's true allergy status and avoid unnecessary avoidance of penicillins 1.

From the FDA Drug Label

NOTE: Reports indicate an increasing number of strains of staphylococci resistant to penicillin G, emphasizing the need for culture and sensitivity studies in treating suspected staphylococcal infections Other groups, including group D (enterococcus) are resistant Although no controlled clinical efficacy studies have been conducted, The FDA drug label does not answer the question.

From the Research

Penicillin Sensitisation

• Penicillin sensitisation is a common issue, with approximately 10% of the US population reporting allergies to penicillin 2
• However, clinically significant IgE-mediated or T lymphocyte-mediated penicillin hypersensitivity is uncommon, affecting less than 5% of the population 2
• Penicillin allergy can be evaluated using a penicillin allergy history algorithm (PAHA) and subsequent penicillin skin testing (PST) 3
• Skin-test negative patients can be transitioned to first-line β-lactam antibiotic therapy, avoiding the use of broad-spectrum antibiotics that increase the risk for antimicrobial resistance 3

Desensitisation Procedures

• Oral desensitisation is an effective and relatively safe approach to administering beta-lactam antibiotics to penicillin-allergic patients with life-threatening infections 4
• Desensitisation procedures involve gradually increasing doses of penicillin, starting with a small dose and doubling it at regular intervals, while monitoring for allergic reactions 4
• Full therapeutic doses can be administered intravenously within 5 hours, and skin-test reactions can disappear or diminish in all patients who are retested after desensitisation 4

Risk of Resensitisation

• Resensitisation can occur in patients who have had negative penicillin allergy evaluations, raising the risk of a subsequent reaction on exposure 5
• The decision to retest for sensitisation before subsequent administrations of penicillin should be made on a case-by-case basis, considering the individual patient's risk factors and medical history 5

Alternative Antibiotics

• Fluoroquinolones, vancomycin, macrolides, and tetracyclines can induce both immediate and delayed hypersensitivity reactions, and their use should be carefully considered in patients with penicillin allergy 6
• Skin testing and direct provocation challenge are not always reliable for diagnosing hypersensitivity reactions to these antibiotics, and desensitisation may be necessary in some cases 6