The study aims to evaluate the effectiveness and safety of a collaborative nurse-allergist approach in penicillin allergy delabeling services. It also seeks to assess the impact on patients' quality of life and compare resource utilization and cost-effectiveness between the nurse-allergist collaborative approach and the traditional allergist-led approach.

This study hypothesizes that by involving both nurses and allergists in the delabeling process and categorizing patients based on risk levels, it will achieve comparable success rates, safety, and improvements in patients' quality of life. This approach is expected to offer superior advantages in terms of time efficiency, resource utilization, and cost-effectiveness compared to traditional allergist-led services.

Inclusion Criteria:

• Receiving inpatient or outpatient treatment at a participating hospital during the study period;
• Possessing a documented penicillin allergy label;
• Underwent penicillin allergy evaluation by the nurse-allergist collaborative approach or the traditional allergist-led approach
• Demographic and clinical data required for the study available.

Exclusion Criteria:

• Patients unable to provide a complete medication history or history of penicillin allergy;
• Patients with only emergency or short-term treatment records;
• Patients who have taken steroids, antihistamines, or similar medications within the last 3 days.

Patients treated at a participating hospital who have a documented penicillin allergy label, are evaluated for penicillin allergy through either the nurse-allergist or allergist-led approach, and have available demographic and clinical data.