A sinus headache is a headache caused by a clogged sinus cavity that is sometimes confused with migraine. When a sinus becomes inflamed, usually as the result of an allergic reaction or an infection, the result is a deep, dull ache in the face and adjacent areas of the head.
Like migraine, the pain may be aggravated by movement. If your headache is truly caused by a sinus blockage, you will probably have other symptoms such as fever, nasal discharge, ear sensations and/or facial swelling.
An x-ray will confirm a sinus blockage. Antihistamines or antibiotics are used to treat sinus headaches.