This retrospective, observational, case-control clinical study evaluated the safety and efficacy of nasal drops containing Pistacia lentiscus oil in preventing recurrence of chronic rhinosinusitis during long-term therapy. Adult patients with chronic rhinosinusitis who received isotonic saline wash plus Pistacia lentiscus oil drops were retrospectively compared with patients who received isotonic saline wash alone, with a total treatment duration of 12 months. The primary outcome was change in Sino-Nasal Outcome Test-22 (SNOT-22) scores, while secondary outcomes included ciliary motility, nasal secretion, biofilm presence, cytological changes, adverse events, and safety/tolerability.

Chronic rhinosinusitis (CRS) is a common and recurrent condition associated with significant morbidity and impaired quality of life. Standard treatment approaches often provide only partial or temporary relief, and recurrence rates remain high. Pistacia lentiscus oil has demonstrated anti-inflammatory and mucosal protective properties, supporting its potential role as a preventive tool in CRS management.

This monocenter, non-profit, retrospective observational case-control clinical study was conducted to evaluate the long-term preventive effect of Pistacia lentiscus oil nasal drops on CRS recurrence. One hundred patients aged ≥18 years with diagnosed CRS were retrospectively evaluated and compared between patients receiving isotonic saline wash plus Pistacia lentiscus oil drops (5 drops per nostril twice daily for 30 days, followed by maintenance treatment for 15 days per month over 11 months) and patients receiving isotonic saline wash alone on the same schedule.

The primary endpoint was the change in disease-specific quality of life, measured by the Sino-Nasal Outcome Test-22 (SNOT-22) from baseline to 12 months. Secondary endpoints included assessments of ciliary motility, nasal secretion, presence of biofilm, supranuclear striae, bacterial cells, variations in inflammatory cellularity (neutrophils, eosinophils, mast cells), safety, and tolerability.

Inclusion Criteria:

• Age ≥18 years
• Clinical diagnosis of chronic rhinosinusitis
• Nasal polypoid score ≤1
• ≥4 episodes of recurrence per year
• SNOT-22 score ≥10 Willingness and ability to provide written informed consent

Exclusion Criteria:

• Nasal polypoid score >2
• <4 episodes of recurrence per year
• SNOT-22 score <10
• Known immune disorders
• Neoplastic disorders
• Neurological disorders
• Psychiatric disorders
• Inability to undergo treatment
• Refusal or inability to provide informed consent

Adult patients aged ≥18 years with diagnosed chronic rhinosinusitis (CRS) who underwent long-term treatment with isotonic saline nasal wash plus Pistacia lentiscus oil nasal drops or isotonic saline nasal wash alone in a real-world clinical setting were retrospectively evaluated.