The Sinus, Allergy and Migraine Study (SAMS).

OBJECTIVE: The objective of this study is to classify (according to the current International Headache Society's criteria [ICHD-II]) the headache types that those with self-diagnosed sinus headache experience and to determine barriers to correct diagnosis.
BACKGROUND: The American Migraine Study II estimates that 28 million Americans suffer from migraine headache. The majority of these patients remain undiagnosed and many are erroneously diagnosed as having sinus headache. Despite this common diagnosis, the concept of sinus headache remains an enigma with a relative paucity of information in the literature.
METHODS: Advertising in the greater Phoenix, U.S. metropolitan area was used to recruit 100 willing and consecutive subjects to participate in this descriptive clinical study (The Sinus, Allergy and Migraine Study [SAMS]). All patients who believed they suffered from sinus headache and were over 18 years of age were enrolled without exclusion. A detailed history and exam was performed in each patient, and patients were given headache diagnoses based on the current International Headache Society's (IHS) criteria.
RESULTS: Of the 100 subjects with self-diagnosed headache, IHS diagnoses mistaken as sinus headache included migraine with or without aura (52%), chronic migraine associated with medication overuse versus probable medication overuse headache (11%), probable migraine (23%), cluster headache (1%), hemicrania continua (1%), headache secondary to rhinosinusitis (3%), and headaches nonclassifiable (9%). Weather changes (83%), seasonal variation (73%), exposure to allergens (62%), and changes in altitude (38%) were frequent migraine triggers. Seventy-six percent of migraine subjects reported pain in the distribution of the second division of the trigeminal nerve (either unilateral or bilateral), and 62% experienced bilateral forehead and maxillary pain with their headaches. The most common associated features included nasal congestion (56%), eyelid edema (37%), rhinorrhea (25%), conjunctival injection (22%), lacrimation (19%), and ptosis (3%). The headaches nonclassifiable were characterized by a bilateral maxillary pressure of mild to moderate intensity associated with at least one cranial autonomic symptom. Features suggestive of migraine were absent in all 9 of these nonclassifiable cases.
CONCLUSIONS: The majority of those with self-diagnosed sinus headache have migraine or probable migraine. In those patients with migraine, the most common reasons for misdiagnosis include headache triggers, pain location, and associated features ("guilt by provocation, location, and association") commonly attributed to sinus headache. The clinician must be aware of these unique presentations of migraine so that a correct diagnosis can be made and effective treatment instituted. A portion of patients with self-diagnosed sinus headache suffer from a headache type, which is unclassifiable by the current IHS criteria. These headaches are characterized by bilateral maxillary pressure, mild to moderate pain intensity, cranial autonomic symptoms, and the complete absence of migraine features.