Intranasal corticosteroids are used to treat allergies, nasal polyps, and sinusitis. These medications work by reducing inflammation in your nasal passages, which helps to relieve symptoms like congestion, sneezing, and runny nose. Intranasal corticosteroids are available as nasal sprays, making them easy to use. Examples include fluticasone propionate (Flonase Allergy Relief), triamcinolone (Nasacort Allergy), and ciclesonide (Omnaris). You can choose the one that best fits your needs based on your symptoms and preferences.