in children, whereas secondary (referred) pain is more common in adults. Primary ear pain is most commonly caused by infection or injury to one of the parts of the ear. External ear Many conditions involving the external ear will be visible to the naked eye. Because the external ear is the most exposed portion of the ear, it is vulnerable to trauma or environmental exposures. Blunt trauma, such as a blow to the ear, can result in a hematoma, or collection of blood between the cartilage and perichondrium of the ear. This type of injury is particularly common in contact sports such as wrestling and boxing. Environmental injuries include sunburn, frostbite, or contact dermatitis. Less common causes of external ear pain include: Auricular Cellulitis: a superficial infection of the ear that may be precipitated by trauma, an insect bite, or ear piercing Perichondritis: infection of the perichondrium, or fascia surrounding the ear cartilage, which can develop as a complication of untreated auricular cellulitis. It is important to identify and treat perichondritis with antibiotics to avoid permanent ear deformities. Relapsing polychondritis: a systemic inflammatory condition involving cartilage in many parts of the body, but often including the cartilage of both ears. The severity and prognosis of the disease varies widely. Otitis externa Otitis externa, also known as "swimmer's ear", is a cellulitis of the external ear canal. In North America, 98% of cases are caused by bacteria, and the most common causative organisms are Pseudomonas and Staph aureus. Risk factors include exposure to excessive moisture (e.g. from swimming or a warm climate) and disruption of the protective cerumen barrier, which can result from aggressive ear cleaning or placing objects in the ear. Malignant otitis externa is a rare and potentially life-threatening complication of otitis externa in which the infection spreads from the ear canal into the surrounding skull base, hence becoming an osteomyelitis. It occurs largely in diabetic patients. It is very rare in children, though can be seen in immunocompromised children and adults. Pseudomonas is the most common causative organism. The pain tends to be more severe than in uncomplicated otitis externa, and laboratory studies often reveal elevated inflammatory markers (ESR and/or CRP). The infection may extend to cranial nerves, or rarely to the meninges or brain. Examination of the ear canal may reveal granulation tissue in the inferior canal. It is treated with several weeks of IV and oral