Orbital cellulitis is an infrequent complication of acute ethmoiditis possibly leading to life- or visual-threatening complications. Despite its natural history is well known, its clinical evolution may widely vary among patients, and even in the most favourable cases long-term sequelae may persist. We here provide a step-by-step iconographic description of a periorbital and orbital cellulitis occurring in a child with ipsilateral acute rhinosinusitis. Our report shows that an unusual long-term evolution of periorbital and orbital cellulitis is possible also in apparently favourable cases.