A patient presents with a rapidly spreading, diffuse, warm, firm facial swelling with poorly defined borders following a dental infection. This best describes:

Cellulitis is an acute, diffuse, spreading soft-tissue infection that is indurated (firm), warm, tender, and poorly demarcated. It can threaten the airway and is a potential emergency (e.g., Ludwig angina).Other options: A chronic abscess is localized and fluctuant with defined borders; a mucocele and fibroma are painless, non-infectious swellings.Key exam takeaway: Diffuse, firm, spreading, poorly defined = cellulitis (emergency if airway/spaces involved); localized and fluctuant = abscess.