Abstract
BACKGROUND: Ten percent of the population self-report an allergy to penicillin, however, less than 10% of these patients are confirmed so (Patterson and Stankewicz 2018). Nonetheless, only the minority (10%) of this population is referred for testing (Jain et al. 2014). Alternative broad spectrum antibiotics are ordered, often expensive and increasing the risk of antibiotic resistance (Jain et al. 2014). OBJECTIVES: To demonstrate the practicality, safety, and importance of “in-clinic” amoxicillin oral challenges (OCs) in suspected penicillin allergic population. DESIGN/METHODS: A retrospective chart review was conducted at a community allergy clinic over a period of 2 ½ years. Children referred for penicillin allergy assessment were skin tested to the allergen components of penicillin and aminopenicillin as per standard protocol. Children with positive skin testing were diagnosed as penicillin allergic. Children with negative skin testing were challenged with amoxicillin at home or in-clinic. Families were requested to communicate results of home challenge. In-clinic amoxicillin OC entailed administering 25 mg of amoxicillin followed by a 30 min monitoring period, and if no reaction occurred, a second dose of 225 mg of amoxicillin was given followed by another 30 min monitoring period. Children were diagnosed allergic if a rash or other signs of allergic reaction developed. RESULTS: Two hundred and three children (mean age 6.3 years) were skin tested; 188/203 (92.6%) were negative and 15/203 (7.4%) were positive. OCs were performed in 181/188 (96.3%). Home challenges were carried out in 110/181 (60.8%) and in-clinic challenges in 71/181 (39.2%).Only 41/110 (37.3%) families communicated outcome of home OCs, resulting in an incomplete diagnosis in the remainder 69/110 (62.7%) children. Thirty nine of 41 (95.1%) home OCs were tolerated, 2/41 (4.9%) had delayed allergic reactions (rashes). Sixty nine of 71 (97.2%) in-clinic OCs were tolerated, 2/71 (2.8%) had delayed allergic reactions (rashes). All in-clinic OCs were safe and resulted in complete diagnosis of tolerance to penicillin during visit. Twenty two of 203 (10.8%) did not proceed onto OC because of positive skin test (15) or previous diagnosis of serum sickness (7). CONCLUSION: Penicillin allergy remains over-diagnosed in the community. Skin testing, where available, helps identify patients for amoxicillin challenge. In-clinic OC to amoxicillin assists in confirming tolerance quickly and more effectively than home challenges. Publications for in-clinic amoxicillin OCs, even without skin testing, have been equally effective in ruling out penicillin allergy (Confino-Cohen et al. 2017). Reintroduction of penicillin in pediatrics can occur safely and simplify future antibiotic use.