Unlike antihistamines, nasal cortisone sprays take several days to begin working. Nasal sprays are often prescribed in combination with antihistamines. These drugs also help control the symptoms but not the causes of allergies. Decongestants shrink swollen membranes in the nose, making it easier to breath. They can either be administered orally or by nasal spray.
Caution is advised when using nasal sprays.
Allergy desensitization or immunotherapy. This type of treatment is usually reserved for those persons who do not respond to the above medications. Allergy immunotherapy stimulates the immune system with gradually increasing doses of the substances to which the person is allergic. This type of treatment usually takes six months to a year to become effective and the injections may be required for three to five years. Allergy injections must be managed by a physician.