Inclusion criteria Exclusion criteria
The age of patients ranged between 18 and 40 years. Endoscopic or radiological evidence of nasal polyposis patients included in patients with pre-existing olfactory dysfunction, rhinitis, rhinosinusitis, and other upper respiratory tract symptoms.
Patients with COVID-19 ˂ 12 weeks. Corticosteroid use (nasal, oral, or intravenous) since positive COVID-19 swab.
Negative Polymerase Chain Reaction (PCR) Pregnant or breast-feeding females.
Patients presented with loss of smell with or without taste > 4 weeks. History of neurodegenerative disease (ie. Alzheimer’s dementia, parkinson’s disease, frontotemporal dementia).
History of an allergic reaction to theophylline or vitamin A.
Patients with vitamin A, steroid and theophylline dependence for comorbid conditions such as asthma and COPD (nasal or systemic).