[Clinical review of 33 cases of rhinitis medicamentosa by decongestant nasal spray]. 
Long-term use of decongestant nasal spray (alpha adrenergic agonist) causes nasal congestion by rhinitis medicamentosa.  We clinically reviewed the cases of 33 patients of rhinitis medicamentosa (23 men, 10 women; mean age, 44.4±15.6 years) treated with nasal steroid sprays instead of decongestant nasal sprays in our clinic from October, 2011 to December, 2012.  Periods of drug use were generally long.  Only 7 cases had a duration of use less than 1 year, and about half (48.5%) had a duration of use longer than 2 years.  Causes of use included acute inflammation (n=6), chronic rhinosinusitis (n=2), and allergic rhinitis (n=20) and unknown cause (n=5).  About two-third of the patients failed to answer questions concerning their use of decongestant nasal spray in a questionnaire prior to examination; therefore, careful observation was necessary.  Among the 33 cases, 31 were followed up, all of whom showed improvement and stopped using decongestant nasal spays within 4 weeks.  Periods for recovery were as follows: 3 days in 19 cases (61.3%) and 1 week in 25 cases (80.6%).  Duration of drug use did not correlate with the period required for recovery; therefore, these results suggest that patients with long-term drug use are able to improve quickly.  Rhinitis medicamentosa with nasal congestion appears readily reversible with suitable treatment.