Non-allergic rhinitis with eosinophilia syndrome treated with mepolizumab: A case report

Non-allergic rhinitis with eosinophilia syndrome (NARES) is a chronic inflammatory rhinopathy characterized by nasal obstruction, rhinorrhea, sneezing and/or an itchy nose. Although eosinophilic nasal cytology is common in NARES patients, identifying the condition is challenging due to a lack of consensus on the diagnostic processes and the role of nasal cytology in clinical practice. Patients may undergo several allergy tests with negative or inconclusive results and are eventually diagnosed with idiopathic/aspecific rhinitis. Treatment options may include intranasal corticosteroids, intranasal antihistamines or a combination of both types of medication. This case report describes a patient with NARES who was unresponsive to conventional therapies and experienced significant improvement after treatment with Mepolizumab, a drug approved for severe asthma with hypereosinophilia, hypereosinophilic syndrome (HES), chronic rhinosinusitis with nasal polyposis (CRSwNP) and eosinophilic granulomatosis with polyangiitis (EGPA). Mepolizumab was administered once a month at a dose of 100 mg subcutaneously. The patient experienced a complete remission of symptoms a year after starting the off-label treatment. Blood counts remained stable and no adverse effects were observed. Mepolizumab appears to be a potential therapeutic alternative in patients with NARES who are unresponsive to conventional therapies.