A blood test, known as the RAST test, can be used to diagnose allergies, although this test is more expensive and less sensitive than skin testing. Be aware that there are unconfirmed tests available, such as cytotoxic testing and others, which have not been proven to be valid. Vasomotor rhinitis, also called perennial nonallergic rhinitis, is characterized by congestion and a runny nose triggered by changes in temperature, barometric pressure or humidity, drafts, irritants, strong smells, ingestion of alcohol, emotional stress or air pollution. Rhinitis medicamentosa may be caused by a rebound effect after withdrawal of topical nasal decongestants. Nasal congestion may also be associated with the administration of some oral medications including oral contraceptives and antihypertensives.
Some women experience nasal congestion during pregnancy and just before their menstrual period.
It not only makes intuitive sense that at-risk individuals should avoid exposure to triggering allergens, but also the usefulness of this approach has been confirmed in multiple studies. Antihistamines block histamine's actions, such as itching, sneezing and a runny nose, as well as itching and swelling of the eyes. Antihistamines are not particularly effective in reducing nasal congestion. Nasal corticosteroids reduce nasal swelling, irritability, mucus secretion and inflammation, among many other actions. They are effective in most patients.