A common drug, an uncommon reaction: The combination of amoxicillin-clavulanic acid induced acute allergic reaction with urticaria and angioedema—A case study

Abstract

Background

Amoxicillin-clavulanic acid is a commonly prescribed β-lactam antibiotic combination known for its broad-spectrum activity and general tolerability. However, it can rarely cause severe immediate hypersensitivity reactions, including urticaria, angioedema, and life-threatening anaphylaxis. Early identification and management are crucial, especially in perioperative settings.

Case presentation

The patient who was a 38-year-old female gynaecologist, developed an acute allergic reaction with urticaria, angioedema, and anaphylaxis shortly after intravenous administration of amoxicillin-clavulanic acid during an elective caesarean section. Despite previous uneventful exposures and no known allergy history, she experienced rapid cardiovascular collapse requiring advanced resuscitation. The patient recovered fully after timely intervention with corticosteroids, vasopressors, and supportive care.

Pathogenesis

The hypersensitivity was likely IgE-mediated, involving mast cell activation triggered by both amoxicillin and clavulanic acid sensitization. Proposed mechanisms include drug-induced hapten formation and disruption of skin cell adhesion proteins, leading to immune activation and the characteristic skin manifestations.

Diagnosis and management

Diagnosis relied on clinical correlation of symptoms with drug exposure. Immediate cessation of the drug and initiation of corticosteroids, antihistamines, vasopressors, and cardiopulmonary resuscitation were critical to patient survival. Close monitoring post-event ensured recovery and prevented complications.

Contribution of this study

This case underscores the unpredictable nature of severe β-lactam allergies, highlighting the necessity for vigilant allergy assessment and pharmacovigilance. It supports the implementation of penicillin skin testing and awareness of clavulanate-specific hypersensitivity. Additionally, pharmacogenomic insights may enhance personalized antibiotic therapy and reduce adverse reactions.

Conclusion

Anaphylaxis to amoxicillin-clavulanate may occur despite prior tolerance, indicating delayed sensitization. Early drug withdrawal and epinephrine use are lifesaving. Pregnancy at advanced maternal age may heighten immune reactivity. Post-resuscitation pulmonary complications warrant monitoring. Confirmatory allergic testing for β-lactam and clavulanate determinants is crucial for guiding future antibiotic safety and prophylaxis.