Infections of the Ear and Mastoid Infections of the ear and associated structures can involve both the middle and external ear, including the skin, cartilage, periosteum, ear canal, and tympanic and mastoid cavities. Both viruses and bacteria are known causes of these infections, some of which result in significant morbidity if not treated appropriately. Infections of the External Ear Structures Infections involving the structures of the external ear are often difficult to differentiate from noninfectious inflammatory conditions with similar clinical manifestations. Clinicians should consider inflammatory disorders as a possible cause of external ear irritation, particularly in the absence of local or. | Chapter 031. Pharyngitis Sinusitis Otitis and Other Upper Respiratory Tract Infections Part 5 Infections of the Ear and Mastoid Infections of the ear and associated structures can involve both the middle and external ear including the skin cartilage periosteum ear canal and tympanic and mastoid cavities. Both viruses and bacteria are known causes of these infections some of which result in significant morbidity if not treated appropriately. Infections of the External Ear Structures Infections involving the structures of the external ear are often difficult to differentiate from noninfectious inflammatory conditions with similar clinical manifestations. Clinicians should consider inflammatory disorders as a possible cause of external ear irritation particularly in the absence of local or regional adenopathy. Aside from the more salient causes of inflammation such as trauma insect bite and overexposure to sunlight or extreme cold the differential diagnosis should include less common conditions such as autoimmune disorders . lupus or relapsing polychondritis and vasculitides . Wegener s granulomatosis . Auricular Cellulitis Auricular cellulitis is an infection of the skin overlying the external ear and typically follows minor local trauma. It presents with the typical signs and symptoms of a skin soft tissue infection with tenderness erythema swelling and warmth of the external ear particularly the lobule but without apparent involvement of the ear canal or inner structures. Treatment consists of warm compresses and oral antibiotics such as dicloxacillin that are active against typical skin and soft tissue pathogens specifically S. aureus and streptococci . IV antibiotics such as a first-generation cephalosporin . cefazolin or a penicillinase-resistant penicillin . nafcillin are occasionally needed for more severe cases. Perichondritis Perichondritis an infection of the perichondrium of the auricular cartilage typically follows local trauma . ear .
