Do Steroids Lower CRP Levels?
Corticosteroids significantly reduce C-reactive protein (CRP) levels rather than raising them. This anti-inflammatory effect is well-documented across multiple clinical contexts and represents a key mechanism of steroid action.
Mechanism of CRP Reduction
- Corticosteroids suppress CRP production by reducing proinflammatory gene transcription and decreasing inflammatory cytokines (particularly IL-6 and TNF-α) that stimulate hepatic CRP synthesis 1
- The anti-inflammatory actions include reducing airway inflammatory cell infiltration and suppressing proinflammatory mediators, cell chemotactic factors, and adhesion molecules 1
Clinical Evidence of CRP Reduction
Community-Acquired Pneumonia Studies
- In a large randomized controlled trial of 711 hospitalized CAP patients, prednisone 50 mg daily for 7 days resulted in a 46% reduction in CRP levels compared to placebo at days 3,5, and 7 (P < .001 for each time point) 2
- Patients with severe CAP and elevated CRP >150 mg/L who received methylprednisolone showed more rapid decline in CRP levels compared to placebo 1
Kawasaki Disease
- In the RAISE trial of 248 high-risk Kawasaki disease patients, the addition of prednisolone to standard therapy resulted in more rapid resolution of fever and decline in CRP levels 1
Important Clinical Distinction
- While steroids lower CRP, they paradoxically increase white blood cell and neutrophil counts (mean increase of 27% for leukocytes and 33% for neutrophils) 2
- This creates a dissociation where CRP falls but leukocytosis persists, which is important for clinical interpretation
Practical Implications for Monitoring
- Procalcitonin (PCT) levels are NOT significantly affected by corticosteroid therapy, making PCT a more reliable marker for monitoring infection resolution in patients receiving steroids 2, 3
- The time-dependent decay of both PCT and CRP during adequate antibiotic treatment is not modified by corticosteroids, though baseline CRP levels are suppressed 3
Clinical Caveats
- When evaluating a patient on steroids with low or normal CRP, clinicians should not be falsely reassured—the steroid effect may be masking significant underlying inflammation or infection 2
- In inflammatory rheumatic diseases, both disease activity AND steroid therapy contribute to altered inflammatory markers, though multivariate analysis suggests inflammatory activity plays the major role 4
- CRP values >10 mg/L in a patient on steroids should prompt investigation for significant infection or inflammation, as the steroid effect would typically suppress CRP below this threshold 1, 5