Sinus headache is commonly diagnosed when patients have facial pain and pressure accompanying their headache. However, acute sinus headache is not as common as believed; the headache must accompany acute bacterial rhinosinusitis, a diagnosis that is based both on clinical and radiologic evidence. Many patients who are diagnosed with sinus headache and treated with antibiotics have a primary headache, usually migraine. This review covers the most recent definitions, epidemiology, pathophysiology, diagnostics, and treatment of acute bacterial rhinosinusitis and the resulting sinus headache as defined by the International Headache Society. Dr. Gupta updates this article with an expansion of the treatments used for sinus headache.