Unravelling the Allergy Label: A Case of Successful Multi-drug Allergy De-labelling in a Patient

We report the case of a 23-year-old woman with a pre-existing penicillin allergy label from childhood who presented with severe bilateral conjunctivitis and oral mucositis following a prodromal respiratory illness. Her symptoms worsened shortly after receiving doxycycline, raising concern for a drug reaction. Her condition progressed with significant ocular involvement requiring bilateral amniotic membrane grafting and subsequent immunosuppressive therapy. Investigations confirmed Mycoplasma pneumoniae infection, supporting a diagnosis most consistent with Mycoplasma-induced rash and mucositis (MIRM), although Stevens-Johnson syndrome (SJS) could not be fully excluded. Following recovery, a structured allergy work-up was undertaken, including patch testing, intradermal testing and graded oral provocation in accordance with established guidance. All tests were negative, and the patient successfully tolerated amoxicillin, doxycycline and ibuprofen without adverse reactions. This case demonstrates how a structured, multidisciplinary approach to drug allergy evaluation can facilitate de-labelling in patients with complex mucocutaneous presentations, restore access to first-line therapies and improve patient care.