Pertussis in Adolescents: Nonspecific Findings and the Importance of Clinical Vigilance - A Single-Center Retrospective Study

Objective: In adolescents, pertussis commonly presents with a mild, atypical picture that can delay diagnosis, lead to its exclusion from the differential diagnosis list, and sustain community transmission. Typical paroxysms and laboratory abnormalities are frequently absent or subtle. We aimed to describe qPCR-confirmed adolescent cases and highlight diagnostic challenges. Methods: We retrospectively reviewed electronic records of patients presenting to general pediatrics and pediatric infectious diseases clinics between January 2019 and August 2025. Adolescents with a multiplex respiratory panel positive only for Bordetella pertussis were included; co-detections and incomplete data were excluded. Demographics, symptoms, examination and imaging findings, laboratory results, treatment, and disposition were evaluated. Results: Forty-one patients were included (51.2% male); all had received childhood pertussis vaccination. Median age was 15 years (IQR 13–17). Fever and dyspnea were each present in 12.2%; vomiting was not reported. Cough occurred in the 73.2%; among those with cough, duration was ≥2 weeks in the 40.0% and <2 weeks in the 60.0%. No apnea/cyanosis or cough-related facial flushing was documented. On auscultation, crackles were noted in the 4.8% (both diagnosed as pneumonia) and rhonchi with wheeze in the 2.4%. Chest radiography was performed in the 56%; the 39% were abnormal, most commonly increased reticular markings. Routine laboratory parameters were nonspecific. Empiric antibiotics were initiated in the 53% of patients; macrolides were added post-confirmation when initially absent. Conclusion: In adolescents, pertussis often presents atypically with nonspecific examination/laboratory findings, and cough duration alone is insufficiently informative. Reliance on classic features or routine labs risks missed diagnoses. Pertussis should remain in the differential for any adolescent with respiratory symptoms, irrespective of cough duration; clinically suspected cases warrant prompt molecular testing and timely management.