Reported is the case of a 79-year-old woman initially diagnosed with periorbital abscess on the background of a recent upper respiratory tract infection. Unexpectedly, intraoperative findings were that of a haematoma rather than an abscess. Subperiosteal orbital haematoma (SOH) is an extremely rare complication of rhinosinusitis. In contrast to the more common periorbital abscess, it is seldom listed as a complication of sinusitis. A review of reported cases suggests an older patient demographic are affected by SOH in contrast to periorbital abscess which typically affects paediatric patients. Given current demographic trends toward an older patient population with multiple comorbidities, failure to consider SOH as a differential will have important implications on preoperative workup, perioperative care and final outcome for patients. We present this case as a reminder of a rare but important complication of a common disease.