Introduction
This topic covers acute and chronic inflammatory conditions of the head and face that a surgeon must recognise and treat: odontogenic and maxillofacial infections, skin and soft-tissue infections of the face, infections of the salivary glands and paranasal sinuses, and the dangerous intracranial and deep neck complications that can follow them. The emphasis in the exam is on recognising the danger zones, knowing the spread routes, and managing airway and sepsis.
General principles
Most facial infections are mixed, with Staphylococcus aureus and streptococci (including oral anaerobes in odontogenic cases) as the main pathogens. The face and scalp have a rich blood supply with valveless veins that communicate with the cavernous sinus through the facial and ophthalmic veins. This is why infection of the nose, upper lip or orbit can spread to the brain in the 'danger triangle' of the face. Spread also follows fascial planes, so the anatomical space in which pus collects determines the clinical picture.