Decongestant nasal sprays are available over-the-counter in many countries. They work to very quickly open up nasal passages by constricting blood vessels in the lining of the nose. Prolonged use of these types of sprays can damage the delicate mucous membranes in the nose. This causes increased inflammation, an effect known as rhinitis medicamentosa or the rebound effect . Decongestant nasal sprays are advised for short-term use only, preferably 5 to 7 days at maximum. Some doctors advise to use them 3 days at maximum. A recent clinical trial has shown that a corticosteroid nasal spray may be useful in reversing this condition.  Topical nasal decongestants include:
The precise mechanism through which fluticasone propionate affects rhinitis symptoms is not known. Corticosteroids have been shown to have a wide range of effects on multiple cell types (., mast cells, eosinophils, neutrophils, macrophages, lymphocytes) and mediators (., histamine, eicosanoids, leukotrienes, cytokines) involved in inflammation. In 7 trials in adults, fluticasone propionate nasal spray has decreased nasal mucosal eosinophils in 66% of patients (35% for placebo) and basophils in 39% of patients (28% for placebo). The direct relationship of these findings to long-term symptom relief is not known.
Nasal congestion is commonly caused by allergic rhinitis, or hay fever. This occurs when pollen, dust, mold spores, or other allergens are inhaled and irritate the nasal passage. Other causes of nasal congestion include the common cold or flu, a deviated septum, sinusitis or sinus infections, reaction to certain medications. Additionally, nasal congestion occurs in many women during pregnancy. In many individuals, nasal congestion is caused by food allergies. Those who are lactose intolerant often find themselves suffering from a stuffy nose. Your doctor can conduct allergy tests to identify your specific type of food allergy and recommend a new diet. Reducing the amount of dairy in your diet in addition to carbohydrates and sugar can improve the quality of your diet and reduce nasal congestion.