What is the differential diagnosis for neck swelling in pediatric patients?

Differential Diagnosis for Neck Swelling in Pediatrics

Immediate Life-Threatening Considerations

In any child presenting with neck swelling, immediately assess for airway compromise, deep neck infection requiring surgical drainage, and multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19. 1

• Airway obstruction from retropharyngeal or parapharyngeal abscess requires urgent evaluation for stridor, drooling, respiratory distress, or inability to swallow. 1, 2
• Deep neck infections most commonly involve the parapharyngeal space (42.3% of cases), followed by retropharyngeal, peritonsillar, submandibular, and multispace abscesses. 2
• MIS-C presents with neck swelling as part of a constellation including fever ≥3 days, multiorgan involvement, elevated inflammatory markers (CRP, ESR, ferritin), and recent COVID-19 exposure within 4 weeks. 1

Primary Diagnostic Categories

Infectious Etiologies (Most Common)

Reactive lymphadenopathy and adenitis account for the majority of pediatric neck swelling cases, with preceding upper respiratory tract infection being the most common antecedent illness (30.8%). 3, 2

• Reactive lymphadenopathy typically presents with mobile, tender nodes <1.5 cm, recent viral upper respiratory infection, and bilateral distribution. 3
• Bacterial adenitis presents with unilateral neck mass or swelling (82.7%), fever (75%), warmth, erythema, and tenderness on examination. 2
• Deep neck abscesses require imaging when fever, recent antibiotic use, and neck tenderness are present (odds ratio 3.01 for imaging). 3, 2
• Staphylococcus aureus is the most commonly isolated pathogen (22.6% of positive cultures) in deep neck infections. 2

Kawasaki Disease

Kawasaki disease must be urgently identified due to risk of coronary artery aneurysm, presenting with bilateral cervical lymphadenopathy ≥1.5 cm, fever ≥5 days, "strawberry tongue," polymorphous rash, and swollen extremities. 4

• Fever ≥5 days with rash and extremity swelling requires immediate evaluation for Kawasaki disease to prevent coronary complications. 4
• Bilateral cervical lymphadenopathy with associated retropharyngeal edema causes facial and neck swelling. 5

Malignant Etiologies

Lymphoma (Burkitt and diffuse large B-cell) commonly presents with painless bilateral cervical lymphadenopathy in children, with firm, non-tender, fixed nodes >1.5 cm and rapid growth. 4

• Red flags for malignancy include: fixed nodes, firm consistency, size >1.5 cm, ulceration of overlying skin, painless/non-tender characteristics, and duration >2 weeks without fluctuation. 4, 5
• Lymphoma may cause jaw/gingival swelling, difficulty swallowing, and oncologic emergencies including tumor lysis syndrome and airway compromise. 4

Congenital Lesions

Congenital etiologies must be added to differential considerations in children, including thyroglossal duct cysts, branchial cleft cysts, dermoid cysts, and vascular malformations. 1

• Superior herniation of the thymus presents as intermittent midline suprasternal neck mass visible only during increased intrathoracic pressure (crying, straining). 6
• Thymic herniation has characteristic sonographic appearances and requires conservative management as the thymus naturally involutes with age. 6

Diagnostic Algorithm

Clinical Risk Stratification

Determine imaging necessity based on specific clinical features rather than empiric testing for all neck swelling. 3

• High-risk features requiring imaging: 4, 5, 3

  • Duration >2 weeks without fluctuation
  • Fixed nodes (non-mobile)
  • Size >1.5 cm
  • Firm consistency
  • Painless/non-tender
  • Fever with neck tenderness
  • Recent antibiotic use without improvement
  • B-symptoms (fever, night sweats, weight loss)

• Low-risk features (imaging often unnecessary): 3

  • Mobile, tender nodes <1.5 cm
  • Recent viral upper respiratory infection
  • Bilateral distribution
  • Soft consistency

Imaging Approach

Ultrasound is the first-line imaging modality for pediatric neck masses, distinguishing solid from cystic lesions, assessing vascularity, and avoiding radiation exposure. 1, 4

• Point-of-care ultrasound (POCUS) reduces ED length of stay from 154 minutes to 68.5 minutes compared to radiology department ultrasound without increasing 30-day return visits. 7
• Ultrasound differentiates solid from cystic neck lesions and discriminates high-flow from low-flow vascular malformations. 1
• Color-flow Doppler ultrasound characterizes vascular flow in solid lesions. 1

CT neck with IV contrast is indicated for suspected malignancy or deep neck infection requiring surgical drainage, with shorter examination time reducing sedation requirements. 1

MRI neck without and with IV contrast is appropriate for suspected malignancy or deep neck abscess requiring surgical drainage, particularly when detailed soft tissue characterization is needed. 1

Tissue Diagnosis

Excisional or incisional biopsy is preferred for suspected malignancy, with fresh tissue in saline for optimal pathologic evaluation. 4

• Fine needle aspiration can be performed but may be inadequate in children. 4
• Open excisional biopsy should not be performed before imaging and FNA when malignancy is suspected, as this worsens outcomes and risks tumor spillage. 8

Critical Management Pitfalls

The most dangerous error is prescribing multiple courses of antibiotics without definitive diagnosis, which delays cancer diagnosis and worsens outcomes. 5

• Only prescribe a single course of broad-spectrum antibiotics if bacterial infection is suspected with clear evidence (warmth, erythema, tenderness, fever). 5
• Mandatory reassessment within 2 weeks is required to monitor for resolution or progression. 5
• Antibiotics should not be prescribed for a fixed neck mass without clear signs of infection. 8

Among patients with reactive lymphadenopathy (15.4% imaged) and adenitis (32.9% imaged), over 95% are discharged home regardless of imaging, suggesting imaging may not always be necessary in these patients. 3

Low culture yield in pediatric deep neck infections (only 31 of 52 patients had pus cultures obtained) necessitates performing Gram staining and acid-fast staining of pus as early as possible before initiating antimicrobial therapy. 2

Recurrence of deep neck infection should alert to the possibility of an underlying bronchogenic cyst requiring excision surgery. 2