Case report of an unusual allergic reaction to a routine skin prick test performed in an outpatient clinic: Diagnosis, management, and knowledge gaps.

Abstract

The skin prick test (SPT) is a standard procedure in allergy/immunology clinics, crucial for evaluating conditions like allergic rhinitis and food allergies. As a cornerstone in investigating immunoglobulin E-mediated allergy, it plays a vital role in diagnosing allergies, including those triggered by common dust mites like Dermatophagoides pteronyssinus, Dermatophagoides farinae, Euroglyphus maynei, and Blomia tropicalis. Despite its widespread use, adverse reactions to SPT are uncommon (15 per 100,000 patients), though the procedure is not entirely risk-free. This article presents a clinical case involving a 17-year-old female who experienced a moderately delayed allergic reaction 120 minutes post-SPT, managed effectively with subsequent symptom resolution. The patient, with a history of persistent rhinorrhea, itchy nose, eyes, and postnasal drip, sought consultation due to worsening symptoms. Diagnostic measures, including patient-reported outcomes and SPT with a standard aeroallergen panel, revealed sensitization to various allergens. Post-test, the patient reported ocular pruritus, left eyelid swelling, and moderate rhinorrhea, persisting for about 24 hours. On the subsequent medical visit, the patient received rupatadine and deflazacort, leading to symptom resolution within 3 hours. This article delves into a systemic allergic reaction post-SPT, emphasizing the 2 main stages of type I hypersensitivity reactions. While the acute phase involves mast cell-driven mediators within 15 minutes, the delayed phase (4-8 hours) includes de novo cytokine release. Vigilance regarding symptom onset and differentiation between mild and severe reactions is crucial. Notably, the absence of specific waiting time guidelines post-SPT underscores the need for reporting to enhance understanding and subsequent management. Performing these procedures in specialized centers with qualified professionals is essential for effectively managing potential anaphylactic reactions. Addressing these knowledge gaps will contribute to enhanced patient safety during diagnostic procedures.