Allegra - The most common form of allergy among adults and children alike is allergic rhinitis. The problems associated with this form of allergy, however, can be mitigated by medications such as Allegra. Allegra is prescribed for patients who want to get relief from symptoms caused by allergic rhinitis. Allegra is reportedly helpful in giving you relief when you experience allergic symptoms such as itchy and watery eyes and even nasal congestion. Allegra is generally recommended to be taken at least twice a day, preferably in the morning and in the evening.