neoplastic processes Lymphadenopathy of greater than weeks’ duration is considered chronic The clinician caring for a child with lymphadenopathy will benefit from knowledge of the anatomic distribution of nodes in the area and their drainage patterns as described in Figures 47.1 and 47.2 , as well as Table 47.1 The location of lymphadenopathy is often suggestive of a possible cause CAUSES OF LYMPHADENOPATHY BY REGION Cervical Enlargement of cervical lymph nodes is a common presenting sign in a variety of pediatric illnesses In order to narrow the differential diagnosis, it is helpful to identify the time course of swelling (acute or chronic); history or presence of localized infections; occurrence of systemic symptoms; and specific location, symmetry, and characteristics of enlarged nodes Cervical anatomy is complex, however nodes in the region can be classified generally as either superficial or deep Superficial cervical nodes, palpated readily along the anterior and posterior borders of the sternocleidomastoid muscle, drain the shallow structures of the head and neck—particularly the oropharynx, external ear, and parotid In contrast, deep cervical nodes, both superior and inferior, receive lymphatic drainage from a wider area of underlying structures of the head and neck, including the nasopharynx, tonsils and adenoids, larynx, and trachea While there are numerous infectious and noninfectious causes of acute and chronic cervical lymphadenopathy, the most common etiologies in children are infectious (see Chapter 94 Infectious Disease Emergencies ) By far, the most common cause of acute cervical adenopathy in children is reactive adenopathy associated with a viral upper respiratory tract infection Superficial nodes are generally symmetrically enlarged, mobile, and minimally tender Reactive adenopathy may persist for to weeks beyond the resolution of a viral illness However, there should be no progression in the size or the extent of the adenopathy after resolution of symptoms of the virus Another common infectious cause of cervical lymph node enlargement, particularly in preschool-aged children, is lymphadenitis Lymphadenitis occurs when an enlarged node becomes inflamed and tender over the course of a few days, as the result of a viral or bacterial infection Viral adenitis is often associated with fever, conjunctivitis, pharyngitis, or other symptoms of an upper respiratory tract infection and causes acute bilateral swelling Common causes are rhinovirus, adenovirus, enterovirus, influenza virus, respiratory syncytial virus, Epstein–Barr virus (EBV), and cytomegalovirus (CMV) Less commonly, herpes simplex, human herpesvirus type (roseola), or measles, mumps, or rubella are causative agents In contrast, bacterial adenitis typically is unilateral and presents with the rapid onset of a firm, tender, lymph node over to days The overlying soft tissue becomes warm, edematous, and erythematous Fever often accompanies the infection If left untreated, the node may become suppurative, which is