Rhinitis medicamentosa (or RM) is a condition of rebound nasal congestion suspected to be brought on by extended use of topical decongestants (e.g., oxymetazoline, phenylephrine, xylometazoline, and naphazoline nasal sprays) and certain oral medications (e.g., sympathomimetic amines and various 2-imidazolines) that constrict blood vessels in the lining of the nose although evidence has been contradictory.
Presentation
The characteristic presentation of RM involves nasal congestion without rhinorrhea, postnasal drip, or sneezing following several days of decongestant use. [Source: Wikipedia 
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