Clinicians frequently prescribe preoperative systemic steroids to patients with chronic rhinosinusitis with nasal polyps (CRSwNP) to optimize surgical conditions. Moreover, these medications effectively reduce polyp volume and intraoperative bleeding. However, a recent meta-analysis reveals a significant clinical challenge regarding histological assessment. Specifically, the use of these steroids dramatically lowers tissue eosinophil counts (TEC). Consequently, this reduction can mask the underlying eosinophilic endotype during a biopsy. Therefore, physicians must carefully consider the timing of tissue sampling to ensure an accurate diagnosis.

Clinical Impact of Preoperative Systemic Steroids

Researchers conducted a systematic review of 17 studies involving 930 participants to evaluate these effects. Furthermore, they found that systemic steroids significantly decreased both the absolute count and the percentage of eosinophils in nasal tissue. Specifically, the pooled mean difference in tissue eosinophils per high-power field (TEC/HPF) dropped by 36.57. Additionally, the percentage of eosinophils among inflammatory cells decreased by 18.14%. Because these findings were consistent across different doses and durations, the suppressive effect appears robust. Notably, this suggests that the anti-inflammatory action of steroids rapidly clears eosinophils from the mucosa.

Timing and Dosage Considerations

Interestingly, the meta-analysis highlighted a potential exception for certain regimens. For example, low-dose protocols (4.2-18.6 mg/day) lasting seven days or less showed a non-significant reduction in eosinophils. Nevertheless, most standard preoperative guidelines recommend higher doses for clinical efficacy. Thus, if a clinician requires an accurate eosinophilic count for biologic eligibility, they face a diagnostic dilemma. Accordingly, surgeons should consider obtaining an outpatient biopsy before initiating any steroid course. Alternatively, they might use a less suppressive regimen if histologic confirmation is the primary goal. Ultimately, avoiding misinterpretation is essential for personalized management. In fact, obtaining a pre-steroid biopsy remains the most reliable strategy for endotyping.

Frequently Asked Questions

Does the use of preoperative systemic steroids affect the eligibility for biologics?

Yes, significantly. Many biologic therapies require a specific tissue eosinophil threshold for approval. Because systemic steroids lower these counts, an intraoperative biopsy may result in a false-negative, potentially disqualifying a patient who actually has a type 2 endotype.

What is the recommended approach to ensure an accurate histological diagnosis?

Ideally, clinicians should perform a nasal polyp biopsy before starting systemic steroids. If steroids are already administered, the meta-analysis suggests that low-dose, short-term courses (less than 7 days) may have a less suppressive effect on tissue eosinophils compared to standard high-dose regimens.

Disclaimer: This content is for informational and educational purposes only and does not constitute medical advice or a professional relationship. Always seek the advice of a physician or other qualified health provider with any questions you may have regarding a medical condition. Refer to the latest local and national guidelines for clinical practice.

References

1. Chitsuthipakorn W et al. Effect of Preoperative Systemic Steroids on Tissue Eosinophils in CRSwNP: Meta-Analysis. Laryngoscope. 2026 Apr 30. doi: 10.1002/lary.70600. PMID: 42062802.
2. Fokkens WJ et al. European position paper on rhinosinusitis and nasal polyps 2020. Rhinology. 2020;58(Suppl S29):1-464.
3. Schläpfer NR et al. Effect of corticosteroids on tissue eosinophilia in chronic rhinosinusitis: a systematic review and meta-analysis. Rhinology. 2026;64(1):14-25.