The Discrepancy Between White Blood Cell and C-reactive Protein Levels in Group A Streptococcal Necrotizing Soft-tissue Infections.

Background: Group A streptococcal necrotizing soft tissue infection (GAS-NSTI) is a severe condition that can be complicated by streptococcal toxic shock syndrome. Management necessitates multidisciplinary care, including emergency medicine, surgery, plastic surgery, and infectious diseases. Early diagnosis and appropriate therapeutic intervention are essential for GAS-NSTI, as effective prevention strategies have not been established. However, it is often misdiagnosed as cellulitis, resulting in delayed treatment.

Methods: In a single-center retrospective study, 25 patients with GAS-NSTI were analyzed for initial symptoms, vital signs, quick sequential organ failure assessment (qSOFA), and blood test results, comparing those with early-stage (≤3 d) and later-stage (≥4 d) GAS-NSTI.

Results: Twelve patients had their first blood test done 3 days or less (early) after first symptom awareness. The remaining13 patients had their first blood test done at 4 or more days (later) after symptom onset. Early-stage GAS-NSTI showed elevated C-reactive protein (CRP) levels (34.0 ± 11.2 mg/dL) but normal white blood cell (WBC) counts (6.7 ± 4.9/μL), whereas later-stage cases had elevated CRP (29.7 ± 9.0 mg/dL) and WBCs (18.6 ± 10.1/μL, P < 0.001). Seven patients (28%) had a laboratory risk indicator for necrotizing fasciitis (LRINEC) score of 5 or more points (4 from the early-stage group and 3 from the late-stage group). Nineteen patients (76%) had a negative qSOFA score at the initial outpatient visit.

Conclusions: In addition to soft tissue symptoms, elevated creatinine and blood urea nitrogen levels, and thrombocytopenia, high CRP levels with normal WBCs should raise suspicion of early GAS-NSTI, even when laboratory risk indicator for necrotizing fasciitis and qSOFA scores are negative.