Nasal sprays contain various medications that are effective in either controlling or preventing allergy symptoms, according to WebMD. Nasal steroids reduce inflammation and the production of mucus during an allergy attack. These steroids prevent allergy suffers from coughing up discharge from congested lungs.
Decongestant and antihistamine nasal sprays may provide relief from allergy symptoms, notes WebMD. Decongestant nasal sprays alleviate swollen nasal passages without causing insomnia. People with high blood pressure or heart disease should use decongestant sprays cautiously. While antihistamine nasal sprays are effective in treating allergy symptoms, they also cause drowsiness. It is best to use antihistamine sprays as a preventative treatment before symptoms appear.