Hoagland Sign-A Common Diagnosis Preceded by an Uncommon Sign.

Infectious mononucleosis, usually caused by Epstein-Barr virus (EBV), typically presents with fever, asthenia, pharyngotonsillitis, and lymphadenopathy. Periorbital edema - the Hoagland sign - is a less common but potentially early manifestation. We report a 16-year-old girl with depression who presented with progressive bilateral periorbital edema, fatigue, fever, and myalgia. Examination showed eyelid edema, tonsillar hypertrophy, and cervical lymphadenopathy. Laboratory studies revealed lymphocytosis with atypical lymphocytes, thrombocytopenia, and mild transaminase elevation. A positive Paul-Bunnell test and EBV serologies confirmed acute infection. Her initial symptomatic management later required hospitalization due to worsening oropharyngeal symptoms. This case underscores the importance of recognizing Hoagland sign for timely diagnosis.