A lost track in ICHD 3 beta: A comprehensive review on osmophobia

Abstract

Background Osmophobia (Os) has been reported to be much more prevalent in migraine (M) than in other primary headaches, and its high specificity in the differential diagnosis between M and tension-type headache (TTH) has been reported. Os was included in the ICHD II Appendix as a diagnostic criterion of M. It disappeared in ICHD-3 beta. To understand this choice, we reviewed the literature after 2004. Methods This was a systematic review. We searched in PubMed, MEDLINE and Cochrane library for "osmophobia", "odour/odorphobia AND headache", "odour/odor hypersensitivity AND headache" and "olfactory hypersensitivity AND headache". Results 112 papers cited Os as an accompanying symptom of headache; 16 focused on Os in M diagnosis. With the data from 40 articles, we calculated the pooled prevalence of Os in 14,360 patients (2281 pediatric) affected by M (n = 12,496) and TTH (n = 1864). In M, the prevalence was 48.5% (CI 95% 41.4 to 55.8%) in adults and 23.4% (CI 95% 15.7 to 33.4%) in pediatric patients; in TTH, the prevalence was 8.9% (CI 95% 4.6 to 13.5%) in adults and 7.9% (CI 95% 3.3 to 18.1%) in pediatric patients. Ten of these papers allowed us to calculate the sensibility and specificity of Os in differential diagnosis between M and TTH. In adults, the value of specificity was 94.1% (CI 95% 88.9 to 96.9%), and sensitivity was 51.4% (CI 95% 38.4 to 64.2%). In pediatric patients, specificity was 92.0% (CI 95% 81.9 to 96.7%), and sensitivity was 22.1% (CI 95% 10.1 to 41.8%). Conclusion The literature endorses the inclusion of Os among M diagnostic criteria. On this ground, the decision to remove Os from ICHD 3 beta appears unjustified and a revision of this choice is recommended.

Osmophobia and Odour-triggered Headaches – Review of the Literature and Main Research Centres

“…The majority of studies investigated the presence of osmophobia. There were 13 comparative studies between migraine and other primary headaches or controls without headache, 2,3,5,8,13,14,[17][18][19][20]22,28,31 and 10 that evaluated only migraine patients. 4,6,7,11,15,16,24,26,29,30 As for odour-triggered headache, there were six studies detected, two comparative studies between migraine and other primary headaches, 1,3 two with migraine patients, 7,24 and two case reports.…”

“…In addition, the five authors who have published most of these studies were born in these three countries. [1][2][3][4][5]7,8,14,15,[18][19][20] We do not have a scientific argument for this fact, but curiously these three countries were pioneers in the study of migraine.…”

“…Generally, we observed a severe intolerance to odours, pleasant or unpleasant, during headache attacks. 2,[4][5][6][7][8]10,11,[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] However, a limited number of studies showed that odours may trigger headache attacks in some patients, particularly in migraineurs 1,3,6,7,9,24 and occasionally in cluster headache patients. 12,18 This intolerance to odours is known as osmophobia, and according to two studies that investigated osmophobia in secondary headaches, it occurred during headache attacks only in the primary headaches.…”

“…2 Many researchers have confirmed that osmophobia is a symptom associated with migraine. 2,[4][5][6][7][8]10,11,[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] Despite such research, osmophobia is still not part of the diagnostic criteria for migraine. 34 In recent years, these studies were carried out in several countries.…”

Osmophobia and Odor‐Triggered Headaches in Children and Adolescents: Prevalence, Associated Factors, and Importance in the Diagnosis of Migraine

“…Osmophobia during an attack was defined as “intolerance to odors that usually leads the individual to avoid them. These odors are not necessarily unpleasant when the patient is not suffering from a headache.” 11,36 …”