Causative organism (Mycobacterium bovis BCG (live attenuated vaccine strain) — intrinsically resistant to pyrazinamide; variable low-level isoniazid resistance by BCG strain (WHO, SPIDS, AAP Red Book))
Clinical classification (Local: injection-site ulcer/abscess/keloid · Regional: ipsilateral axillary/cervical/supraclavicular lymphadenitis (non-suppurative or suppurative) · Distant single-site without systemic illness may still need ID evaluation (SPIDS, Cochrane CD008300, Kuyucu 2021))
First-line therapy
Observation ± needle aspiration • —
Duration: 4–6 months (natural history) · Non-suppurative regional lymphadenitis: reassurance and follow-up — most resolve spontaneously without antimycobacterial drugs (Cochrane CD008300, SPIDS, Kuyucu systematic review 2021)
• Observation (no anti-TB drugs): non-suppurative regional lymphadenitis in a thriving child without fever, weight loss, distant nodes, or hepatosplenomegaly — antimycobacterial therapy does not shorten resolution or prevent suppuration (Cochrane CD008300, SPIDS, AAP Red Book).
• Needle aspiration (not antibiotics): suppurative/fluctuant regional lymphadenitis — preferred to prevent sinus formation and shorten healing; use wide-bore needle; may repeat; avoid incision and drainage (SPIDS, Cochrane, Hong Kong Paediatrics).
• Antimycobacterial therapy indicated: progressive enlargement despite aspiration, BCG osteomyelitis/osteitis, persistent regional disease not responding to conservative measures, or any features suggesting dissemination — start isoniazid + rifampicin (± ethambutol) per alternative tier; ID consultation (SPIDS, Consultant360, Oman cohort).
• Pyogenic superinfection only: antibiotics (e.g. anti-staphylococcal) when secondary bacterial infection suspected — distinct from treating BCG itself; culture-directed when possible (SPIDS, AAP Red Book).
• Do NOT use pyrazinamide empirically: M. bovis/BCG is intrinsically pyrazinamide-resistant — PZA provides no benefit and adds hepatotoxicity risk (WHO, SPIDS, AAP Red Book).
Isoniazid • p.o. • 7–10 mg/kg/day • 1×/day
Max 300 mg/day · Duration: 6–12 months · WHO: 10 mg/kg/day (range 7–15 mg/kg), max 300 mg/day — daily; supplement pyridoxine in malnourished/HIV-exposed infants per local protocol
• Isoniazid + rifampicin: progressive regional lymphadenitis not responding to aspiration, large persistent nodes, or specialist decision — 6 months typical for regional disease (RI regimen; Cochrane notes limited evidence for routine use in uncomplicated lymphadenitis).
• Add ethambutol: BCG osteomyelitis/osteitis, extensive regional disease, or when treating closer to disseminated spectrum — three-drug daily therapy per WHO pediatric TB dosing (WHO 2022, SPIDS).
• BCG osteomyelitis: anti-TB therapy usually 6–12 months (up to 18 months if slow response); surgical biopsy/debridement may aid diagnosis and healing — do not rely on antibiotics alone without ID oversight (Consultant360, Oman cohort, Taiwan CDC series).
• Surgical excision of lymph node: only after ≥2 failed needle aspirations, re-accumulation, or node persistently ≥3 cm for >6–9 months — not first-line (SPIDS).
• Immunology referral: any treated BCG complication beyond trivial local reaction, family history of immunodeficiency, consanguinity, or failure to thrive — before or concurrent with antimycobacterial therapy (IEI.CHN 2024 consensus, SPIDS).
Enter weight on Kids to calculate doses
Rifampicin • p.o. • 10–15 mg/kg/day • 1×/day
Max 600 mg/day · Duration: 6–12 months · WHO: 15 mg/kg/day (range 10–20 mg/kg), max 600 mg/day — daily; rifampicin is critical because many BCG strains have low-level INH resistance (SPIDS, AAP Red Book)
Enter weight on Kids to calculate doses
Clinical notes
• Observation vs treatment: uncomplicated non-suppurative regional lymphadenitis and small injection-site reactions require observation only — antimycobacterial drugs do not prevent suppuration or shorten healing (Cochrane CD008300, SPIDS, Kuyucu 2021 systematic review); treat with isoniazid + rifampicin when progressive, osteomyelitis, or dissemination suspected.
• Surgical management: needle aspiration for suppurative regional nodes; avoid incision and drainage (sinus/scar risk); lymph node excision if repeated aspiration fails or node ≥3 cm persistently enlarged >6–9 months; operative biopsy for osteomyelitis or diagnostic uncertainty (SPIDS, AAP Red Book).
• BCG osteomyelitis: rare; presents months to years post-vaccination, often long-bone epiphysis/metaphysis; diagnose with compatible history, imaging, and granulomatous histology/culture; treat with isoniazid + rifampicin ± ethambutol for 6–12+ months — never use pyrazinamide (M. bovis resistant) (Consultant360, Oman 2021, WHO).
• Suspect immunodeficiency when: disseminated or distant anatomic involvement, hepatosplenomegaly, persistent fever, failure to thrive, recurrent mycobacterial disease, or family history — evaluate for SCID, MSMD (IFN-γ/IL-12 pathway), CGD, HIV; ~50% of BCGitis and >90% of BCGosis have PID in cohort studies — urgent immunology/genetics referral (IEI.CHN 2024, SJI 2021, SPIDS).
• Follow-up: review every 2–4 weeks for regional disease — document node size, fluctuance, systemic signs; non-suppurative nodes expected to regress over 4–6 months; return immediately for fever, new distant nodes, bone pain, or poor weight gain; monitor LFTs on anti-TB therapy; report to vaccine pharmacovigilance per local policy (WHO vaccine safety sheet, SPIDS).
• Cochrane — Therapies for BCG-induced disease in children (CD008300) (2013)
• SPIDS — BCG vaccine related lymphadenitis management guidelines (2015)
• Kuyucu et al. — Management of BCG lymphadenitis systematic review (Pediatr Infect Dis J) (2021)
+ 4 more
• AAP Red Book — Tuberculosis and BCG vaccine adverse reactions (2024)
• WHO — Consolidated guidelines: TB in children and adolescents (Module 5) (2022)
• IEI.CHN — Expert consensus on immune assessment and clinical management of BCG vaccine disease (2024)
• Consultant360 — BCG vaccine-related lymphadenitis and BCGitis review (2020)
