What is the appropriate evaluation and treatment for a patient with lymphadenitis?

Lymphadenitis: Evaluation and Treatment

Initial Evaluation: Distinguish Etiology First

The most critical first step is determining whether lymphadenitis is bacterial, tuberculous (TB), or nontuberculous mycobacterial (NTM), as treatment differs fundamentally—TB requires drug therapy and public health tracking, while NTM may be managed surgically, and bacterial cases need empiric antibiotics. 1, 2

Key Clinical Features to Assess

• Age and presentation pattern: NTM lymphadenitis primarily affects children aged 1-5 years (submandibular, submaxillary, cervical, or preauricular nodes), while TB causes >90% of culture-proven mycobacterial lymphadenitis in adults. 1, 2

• Laterality: Unilateral presentation occurs in 95% of NTM lymphadenitis cases. 3

• TB risk factors: Foreign-born status, TB exposure history, positive tuberculin skin test (94% sensitive), and abnormal chest radiograph (present in 38% of TB lymphadenitis cases). 2

• Antecedent viral illness: Viral upper respiratory infections precede 22-53% of lymphadenitis cases and typically cause acute bilateral cervical lymphadenopathy. 1

Essential Diagnostic Workup

• Tuberculin skin test (PPD) in all patients with suspected mycobacterial lymphadenitis. 3

• Chest X-ray to exclude pulmonary TB. 3

• Fine-needle aspiration (FNA) for cytology and culture (mycobacterial and bacterial) in suspected lymphadenitis. 3

• Ultrasound as first-line imaging to differentiate intraparotid versus extraparotid masses and identify discrete, mobile nodules. 3

• Complete blood count, C-reactive protein, erythrocyte sedimentation rate when lymphadenopathy persists beyond 4 weeks or is accompanied by systemic symptoms. 4

Treatment by Etiology

Bacterial Lymphadenitis

Empiric antibiotics covering Staphylococcus aureus and Group A Streptococcus—amoxicillin-clavulanate or cephalexin—should be initiated for acute bacterial lymphadenitis. 3, 2

• Acute unilateral cervical lymphadenitis is caused by streptococcal or staphylococcal infection in 40-80% of cases. 5

Tuberculous Lymphadenitis

Standard 4-drug anti-tuberculosis therapy (isoniazid, rifampin, pyrazinamide, ethambutol) for 6-9 months is the recommended treatment for tuberculous lymphadenitis. 3, 2

• TB lymphadenitis must be treated as systemic disease with antimycobacterial medication. 6

Nontuberculous Mycobacterial (NTM) Lymphadenitis

Complete surgical excision without chemotherapy is the recommended treatment for children with NTM cervical lymphadenitis, achieving approximately 95% cure rate. 7, 3

• MAC causes approximately 80% of culture-proven NTM lymphadenitis, representing a dramatic shift from 30 years ago when M. scrofulaceum predominated. 1

• For adults with localized NTM disease, combination of surgical excision/debridement plus clarithromycin-based multidrug chemotherapy for 6-12 months is recommended. 2

• For recurrent disease in children or when surgical risk is high (e.g., risk of facial nerve involvement with preauricular nodes), use clarithromycin multidrug regimen such as that used for pulmonary disease. 7

HIV-Associated Lymphadenitis

• Disseminated MAC in HIV-infected adults requires macrolide-based therapy (azithromycin or clarithromycin) plus ethambutol, with or without rifabutin. 2

• Immune reconstitution inflammatory syndrome can cause paradoxical lymphadenitis (painful, swollen cervical, axillary, or inguinal nodes) after initiating antiretroviral therapy. 1

Critical Pitfalls to Avoid

• Never perform incisional biopsy or drainage alone for suspected mycobacterial lymphadenitis—this frequently leads to sinus tract formation and chronic drainage; complete excision is preferred for NTM. 7, 1, 2

• Avoid anti-TB drugs without a macrolide for NTM lymphadenitis—this results in treatment failure. 7, 2

• Do not use corticosteroids in unexplained lymphadenopathy—they can mask histologic diagnosis of lymphoma or malignancy. 4, 8

• Distinguish TB from NTM before treatment—a difficult clinical problem arises when a child has granulomatous disease with a strongly positive PPD (e.g., 15 mm); initiate anti-TB therapy while awaiting culture results, especially with TB risk factors, and discontinue if cultures fail to yield mycobacteria. 7

Red Flags Requiring Urgent Evaluation

• Lymph nodes larger than 2 cm, hard, or matted/fused to surrounding structures may indicate malignancy or granulomatous diseases. 4

• Supraclavicular or posterior cervical nodes carry much higher malignancy risk than anterior cervical nodes. 1

• Overlying skin changes and multiple or bilateral nodal diseases are significantly associated with de novo disease or recurrence in NTM lymphadenitis. 9