Localized:

Generalized:

Acute infective lymphadenitis is a problem frequently encountered in the pediatric population. It represents a primary infection of the lymph node. The causative organism frequently gains entry into the body through the pharynx, nares, dentition, or a break in the skin. The etiology is most often bacterial, with S. aureus being the most frequently isolated organism. Other pathogens that may be found include group A streptococci, Mycobacterium tuberculosis, atypical mycobacteria, gram-negative bacilli (such as B. henselae), Haemophilus influenzae, anaerobic bacteria, Francisella tularensis, and Yersinia pestis.

Physical examination usually reveals a unilateral, tender, warm, often fluctuant lymph node with erythema of the overlying skin. Fever and elevated white blood cell count occur occasionally, most often in the younger child.

Aspiration often reveals the cause and may provide symptomatic relief if the lymph node is large or in an awkward position. In uncomplicated cases, treatment with an oral antibiotic is frequently all that is needed. Recent increases in antibiotic resistance such as methicillin-resistant S. aureus may impact the choice of antibiotics. Infants, children who appear clinically ill or have an underlying immunodeficiency, those who do not improve or progress on oral antibiotics and those who develop associated cellulitis should be admitted to the hospital for intravenous antibiotics and further evaluation.

Reactive hyperplasia of lymph nodes represents a response to antigenic stimuli (foreign material, cellular debris, or infectious organisms and their toxic products).

The resulting lymphadenopathy can be acute or chronic. The cervical, axillary, and inguinal nodes are most commonly involved and can sometimes grow to be quite large. The nodes clinically enlarge secondary to infiltration with histiocytes or plasma cells. Acute cellular infiltration and edema causes distention of the capsule, producing tenderness when the lymph node is palpated.