What is the appropriate diagnosis and treatment for unilateral cervical lymphadenopathy?

Unilateral Cervical Lymphadenopathy: Diagnosis and Treatment

For unilateral cervical lymphadenopathy (swollen glands on one side of the neck), the initial approach depends critically on distinguishing between acute bacterial infection, chronic/subacute causes (particularly mycobacterial infections), and malignancy—with antibiotics reserved only for clear signs of acute bacterial infection, and excisional biopsy being the definitive diagnostic procedure when the etiology remains unclear after initial evaluation. 1, 2

Initial Clinical Assessment

Key Historical and Physical Examination Features

Determine the acuity and associated symptoms:

• Acute presentation (days) with fever, warmth, erythema of overlying skin, localized tenderness, and tachycardia suggests bacterial lymphadenitis (Staphylococcus aureus or Group A Streptococcus in 40-80% of cases) 2, 3
• Subacute/chronic presentation (weeks to months) without acute inflammatory signs suggests mycobacterial infection (tuberculosis or nontuberculous mycobacteria), cat scratch disease, toxoplasmosis, or malignancy 1, 3
• Unilateral presentation is typical for nontuberculous mycobacterial (NTM) lymphadenitis (95% of cases) and certain other infections 1, 4

Assess specific risk factors:

• Age 1-5 years: Peak incidence for NTM cervical adenitis due to environmental exposure to soil and water; approximately 80% of culture-proven NTM lymphadenitis is due to Mycobacterium avium complex 1, 4
• Adults: Over 90% of mycobacterial cervical adenitis is M. tuberculosis 4
• Fixed, firm, or ulcerated nodes are highly suspicious for malignancy 1
• Supraclavicular or posterior cervical location carries much higher malignancy risk than anterior cervical nodes 3

Rule out urgent conditions:

• Kawasaki disease: Consider if fever ≥5 days with unilateral cervical lymphadenopathy ≥1.5 cm (usually anterior cervical triangle), especially in children <6 months who have highest risk of coronary complications 2
• Look for additional features: bilateral nonexudative conjunctivitis, oral changes (cracked lips, strawberry tongue), polymorphous rash, or extremity changes 2

Management Algorithm

For Acute Bacterial Lymphadenitis (Clear Inflammatory Signs Present)

Prescribe antibiotics only when clear signs of bacterial infection exist: warmth, erythema, localized tenderness, fever, tachycardia, or recent upper respiratory infection/dental problem 2

• Provide coverage for both Staphylococcus aureus and Group A beta-hemolytic streptococci 3
• Reassess within 2 weeks: If the mass has not completely resolved, proceed immediately to malignancy workup, as partial resolution may represent infection in an underlying malignancy 2

Critical pitfall: Never prescribe multiple courses of antibiotics without clear bacterial infection signs, as this delays malignancy diagnosis 2

For Subacute/Chronic or Unclear Etiology

Do NOT give empiric antibiotics in the absence of acute bacterial infection signs 2

Obtain baseline laboratory testing:

• ESR, CRP, CBC with differential (looking for granulocytosis vs lymphocytosis) 2
• LDH and platelet count (thrombocytopenia associated with malignancy) 5
• Tuberculin skin test (PPD) if mycobacterial infection suspected 1, 4

Imaging considerations:

• Ultrasound is the preferred initial imaging modality in children (non-radiating) 6
• Contrast-enhanced CT or MRI for patients at increased risk for malignancy or for surgical planning 2, 7
• Ultrasound features suggesting malignancy: bulky lesion, absence of hilus, blurred outer contour, abnormal Solbiati-index 5

Tissue diagnosis:

• Fine-needle aspiration (FNA) is the preferred initial tissue sampling method over open biopsy 2
• Excisional biopsy has >95% diagnostic yield and should be performed when definitive diagnosis is needed 1, 2
• Core biopsy is an effective alternative with 90% diagnostic accuracy, offering faster diagnosis and avoiding surgery 8

Specific Conditions Requiring Targeted Treatment

Nontuberculous Mycobacterial (NTM) Lymphadenitis:

• Excisional surgery without chemotherapy is the treatment of choice with approximately 95% success rate 1
• For larger lymph nodes (≥5 cm), difficult anatomical sites, recurrent disease, or high surgical risk: consider clarithromycin-based multidrug regimen with corticosteroids 1
• Important distinction: Only ~10% of culture-proven mycobacterial cervical lymphadenitis is tuberculosis, but this distinction is critical for treatment and public health tracking 1

Lymphogranuloma Venereum (LGV):

• Most frequent manifestation in heterosexual men is tender inguinal/femoral lymphadenopathy, usually unilateral 9
• Recommended treatment: Doxycycline 100 mg orally twice daily for 21 days 9
• Alternative: Erythromycin base 500 mg orally four times daily for 21 days 9
• Buboes may require aspiration through intact skin or incision and drainage 9

Follow-Up Strategy

If lymph node completely resolves: Schedule one additional follow-up in 2-4 weeks to monitor for recurrence 1

If lymph node persists ≥2 weeks without significant fluctuation: This places the patient at increased risk for malignancy or chronic infection; proceed to definitive workup 1

Reactive lymphadenopathy from respiratory infections typically resolves within days of completing treatment or with resolution of infectious symptoms 1

Key Pitfalls to Avoid

• Never assume a cystic neck mass is benign without definitive diagnosis 2
• Do not mistake NTM lymphadenitis for bacterial infection and treat with inappropriate antibiotics 1
• Avoid multiple antibiotic courses without clear bacterial signs, as this delays critical diagnoses 2
• Recognize that partial resolution after antibiotics may represent infection in underlying malignancy 2