Lymphadenitis is seen in association with a variety of pharyngeal, dental, skin or other head and neck infections [6]. Cervical adenitis with abscess formation or suppurative cervical lymphadenitis may develop in some cases of lymphadenopathy. Microorganisms penetrate the skin or mucosal surfaces of the head or neck and are cleared via lymphatic vessels to regional lymph nodes. In the lymph nodes T cell proliferation results node enlargement. In response to invasion of bacterial, viral, mycobacterial or fungal pathogens, additional inflammatory cells, specifically neutrophils, may be recruited to the site of infection. In most instances, disruption of mucosal tissues can result in subsequent invasion by group A streptococcus, other colonizing pathogens or oropharyngeal flora (anaerobes) In other instances pathogens invade the nodal tissue hematogenously, as might be the case with Staphylococcus aureus. Cervical lymphadenitis occurs as a result of host inflammatory responses to this invasion. Lymphadenitis may progress to abscess formation as the host defenses attempt to contain the infection. Typically abscess material consist of cellular debris from necrotic tissue, inflammatory cells and microorganisms. The inflammatory cellular infiltrate may form an abscess wall. Although most cervical lymphadenopathy is viral in etiology, suppuration of an inflamed lymph node is suggestive of primary or secondary bacterial infection with abscess formation. These infections are most often due to group A streptococcus and other streptococci, S. aureus or anaerobes as outlined in Table 14.3.

The diagnostic evaluation of a child with an inflammatory neck mass, suspected cervical neck abscess, or suspected deep neck infection involves a detailed history, physical examination, laboratory studies and if indicated, diagnostic imaging. Helpful historical data includes the age of the child, the duration of illness and mass, the specific associated symptoms involving the upper respiratory tract, and the presence of any symptoms suggestive of a systemic process [7]. Furthermore it is helpful to determine if there has been a change in size or consistency (firm vs. soft) of the mass, presence of fever, recent upper respiratory infection. An exposure history is important to determine if the child has had any animal contact, specifically with kittens or cats, close contact with anyone at risk for tuberculosis, or household members with recurrent boils or soft tissue infection as might be present in cases of methicillin resistant S. aureus (MRSA).

The physical inspection of the neck should include the dimensions and location (midline or lateral) of the mass. If the lesion is lateral then it is further described by nodal group or “level” as outlined in Table 14.1. The presence of an overlying discoloration, sinus or fistula, tenderness, palpable consistency (i.e. soft or firm), and its mobility, including the direction of mobility is also important. Tender lesions are commonly inflammatory and a soft or fluctuant consistency is suggestive of either an infected cyst or an abscess. Careful inspection of nasal passages, pharynx, and oral cavity (including teeth and gums) should be performed to determine a possible source of lymphadenitis. The presence of tonsillar exudate is not diagnostic of bacterial infection and can be present in viral (i.e. EBV or adenovirus) infection (Fig. 14.1). Likewise, the absence of exudate does not exclude infection due to group A streptococcus. Careful examination of the scalp and skin should be performed looking for evidence of infected bites, impetigo, or a papule as may be seen in cat scratch disease.

The remainder of the physical examination may provide additional clues as to the etiology of an inflammatory neck mass or a systemic illness. For instance, an enlarged spleen is often associated with mononucleosis and a conjunctivitis and rash may be present in children with adenovirus or Kawasaki disease. A scarlatiniform rash or diffuse erythroderma may be consistent with group A streptococcal infection.

Following a thorough history and physical examination additional diagnostic studies and ancillary laboratory testing may be needed prior to surgical intervention. In specific infections (i.e. tuberculosis) this may prevent unnecessary surgery. Table 14.4 summarizes diagnostic and laboratory testing that may be useful in evaluating a child with neck abscess or deep neck infection.