What is the treatment for lymphadenitis in adults?

Treatment of Lymphadenitis in Adults

In adults with lymphadenitis, the treatment approach depends critically on the underlying etiology: over 90% of mycobacterial lymphadenitis in adults is tuberculous (requiring standard 4-drug anti-TB therapy), while acute bacterial lymphadenitis requires empiric antibiotics covering Staphylococcus aureus and Group A Streptococcus. 1, 2

Initial Diagnostic Approach

The first priority is distinguishing between bacterial, tuberculous, and nontuberculous mycobacterial (NTM) lymphadenitis, as treatment differs fundamentally:

Key Clinical Features to Assess

• Tuberculosis risk factors: History of TB exposure, foreign-born status (particularly within 5 years of arrival), positive tuberculin skin test (94% sensitive), and abnormal chest radiograph (present in 38% of cases) 1, 3
• Acute bacterial features: Rapid onset, tender nodes, fever, cellulitis, and recent upper respiratory infection (present in 22-53% of cases) 2, 4
• NTM characteristics: Insidious onset, unilateral presentation (95%), non-tender nodes, absence of systemic symptoms, and negative TB exposure history 1

Essential Diagnostic Workup

• Tuberculin skin test (PPD) in all patients with suspected mycobacterial lymphadenitis 1, 2
• Chest radiograph to exclude pulmonary tuberculosis 2
• Fine-needle aspiration (FNA) for cytology and culture (mycobacterial and bacterial) - yields positive cultures in 62% of tuberculous cases and identifies granulomas in 61% 2, 3

Treatment by Etiology

Tuberculous Lymphadenitis (Most Common in Adults)

Standard 4-drug anti-tuberculosis therapy for 6-9 months: isoniazid, rifampin, pyrazinamide, and ethambutol 2

• This is the predominant form in adults (>90% of culture-proven mycobacterial lymphadenitis) 1
• Response to therapy is uniformly successful with directly observed therapy 3
• Important caveat: Paradoxical expansion of lymphadenopathy occurs in 20% of patients during treatment, particularly in HIV-positive individuals - this does not indicate treatment failure 3

Acute Bacterial Lymphadenitis

Empiric antibiotics covering Staphylococcus aureus and Group A Streptococcus: amoxicillin-clavulanate or cephalexin 2

• Most acute suppurative cases are caused by S. aureus or Streptococcus pyogenes 4
• Critical consideration: Local methicillin-resistant S. aureus (MRSA) prevalence should guide antibiotic selection 4
• Failure to respond within 48-72 hours warrants diagnostic re-evaluation and consideration of surgical drainage or alternative diagnoses 4

Nontuberculous Mycobacterial (NTM) Lymphadenitis

For localized NTM disease in adults: Combination of surgical excision/debridement plus clarithromycin-based multidrug chemotherapy for 6-12 months 1

• NTM lymphadenitis rarely affects immunocompetent adults (primarily a pediatric disease) 1
• Exception: HIV-infected adults, particularly with immune reconstitution syndrome, may develop NTM lymphadenitis involving cervical, mediastinal, or intraabdominal nodes 1
• The recommended drug regimen is the same as for MAC pulmonary disease (clarithromycin or azithromycin plus ethambutol and rifamycin) 1

Special Populations

HIV-Infected Adults

• Disseminated MAC: Requires macrolide-based therapy (azithromycin or clarithromycin) plus ethambutol, with or without rifabutin 1
• Immune reconstitution inflammatory syndrome (IRIS): May present as suppurative lymphadenopathy with fever after initiating antiretroviral therapy; consider anti-inflammatory therapy or corticosteroids if severe 1
• Excision of accessible nodes may be needed for diagnosis when blood cultures are negative 1

Critical Pitfalls to Avoid

• Never use incisional biopsy or drainage alone for suspected mycobacterial lymphadenitis - this frequently leads to sinus tract formation and chronic drainage 1
• Avoid corticosteroids in unexplained lymphadenopathy as they can mask histologic diagnosis of lymphoma or malignancy 5, 6
• Do not use anti-TB drugs without a macrolide for NTM lymphadenitis - this results in treatment failure 1
• When granulomatous disease is found with a strongly positive PPD (≥15 mm), initiate anti-TB therapy while awaiting culture results, especially with TB risk factors 1

When to Pursue Surgical Intervention

• Excisional biopsy is indicated when FNA is non-diagnostic or when surgical excision is therapeutic (as in pediatric NTM cases) 3
• Surgical drainage may be necessary for suppurative bacterial lymphadenitis not responding to antibiotics 4
• For NTM disease in adults, surgical debridement combined with chemotherapy is the standard approach 1