Recovery of smell sense loss by mepolizumab in a patient allergic to Dermatophagoides and affected by chronic rhinosinusitis with nasal polyps

Abstract Background Chronic rhinosinusitis with nasal polyps (CRSwNP) frequently presents with dysfunction or loss of the sense of smell, resulting in a significant impairment in quality of life. The medical treatments currently available may improve the olfactory function in patients with CRSwNP, but such an outcome is generally only transitory. We report the case of a patient with CRSwNP who completely recovered from smell sense loss by treatment with mepolizumab. Case presentation The patient was a 62-year-old female who has severe asthma induced by allergy to Dermatophagoides and concomitant CRSwNP. Any treatment for the latter, including oral and injective corticosteroids, was unsuccessful in the loss of smell. Due to the satisfaction of admission criteria to mepolizumab treatment for severe asthma, treatment was initiated on March 2018, resulting in good clinical control of both asthma and CRSwNP, and particularly in complete recovery of the smell loss after 4 months of treatment and still persisting. Conclusion In this case report, the treatment with mepolizumab in a patient allergic to Dermatophagoides and affected by CRSwNP was associated with an improvement of anosmia. That finding may be explained by a reduction of the nasal obstruction by nasal polyps.