FIGURE 120.10 Lymphadenitis (Reprinted with permission from Fleisher GR, Ludwig W, Baskin MN Atlas of Pediatric Emergency Medicine Philadelphia, PA: Lippincott Williams & Wilkins; 2004.) Salivary gland infections, sialadenitis and parotitis , may cause lateral neck or submental swelling Most salivary gland infections affect the parotid gland Involvement of the sublingual and submandibular glands are much less common When the parotid gland is involved, firm indurated swelling is found extending in an arc from the preauricular area down beneath the ear or under the mandible The degree of swelling is often sufficient to blunt the angle of the jaw, and the mass is usually mildly tender ( Fig 120.11 ) Patients complain of mild pain in the region of the pinna, which may increase with eating Viral agents (e.g., mumps virus, parainfluenza types and 3, influenza, Coxsackie virus, and rarely, human immunodeficiency virus) cause most of these infections Less commonly, parotitis is due to a bacterial agent such as S aureus In these cases, patients present with rapid gland enlargement and severe pain, and they often have high fever and signs of systemic toxicity On examination, overlying erythema and exquisite tenderness are present, and purulent material can sometimes be expressed from Stensen duct by massaging the gland An elevated amylase level can help confirm the diagnosis of parotitis In patients where the anatomy is obscured by significant swelling, ultrasound can help differentiate parotitis from