My differential for patients complaining of a sinus headache used to be uncontrolled allergic rhinitis versus an upper respiratory tract infection ("common cold"). Sinusitis rarely merits treatment with antibiotics, so I'd look for one of these presumably underlying causes to treat.
It turns out that an important diagnosis has been missing from my differential, and an article in last month's Journal of Family Practice reviews evidence that many, if not most, patients complaining of sinusitis may have a migraine instead.
This article reviewed three cross-sectional studies and and one systematic review. Two of the cross-sectional studies enrolled patients complaining of "sinus" headaches and classified their headaches using the International Headache Society's (IHS) criteria. In both studies, researchers re-classified >80% of enrollees as migraineurs.
The third cross-sectional study divided enrolled headache patients into migraineurs and non-migraneurs, asked about their symptoms, and found the following 5 criteria distinguished those participants with migraines:
- pulsating quality
- duration between 4-72 hours
- unilateral location
- nausea and/or vomiting
- disturbance of daily activity
Photo- or phonophobia, presence/absence of nasal discharge, and aggravation by activity did not distinguish between migraine and sinus headaches in this study.
The systematic review, which was originally published in JAMA, verified those 5 criteria and turned them into a mnemonic, "POUND:"
- Pulsatile in quality
- Duration 4-72 hOurs
- Unilateral location
- Nausea and/or vomiting
- Disabling intensity
This systematic review found that, when 4 or 5 of these criteria are present, the likelihood ratio of a migraine is 24 (which is quite high). An AFP Point-of-Care guide on "Diagnosis of Migraine Headache" includes the POUND criteria along with another clinical decision rule and is definitely worth a read.
Several practical questions remain about applying these findings in practice. Does treating patients complaining of "sinus" who meet IHS migraine criteria with migraine therapies help their headaches? Are patients who felt that they've had "sinus" problems for years accepting of a migraine diagnosis? What about patients who meet IHS criteria for both migraine and sinusitis? I'm hopeful that researchers will address these questions soon.
In the meantime, though, I will add migraine to my differential for patients who complain of a "sinus" headache. Will these studies change how you assess patients complaining of a "sinus" headache?