Abstract
Despite its inclusion in the International Classification of Orofacial Pain, tension-type orofacial pain has little support in the scientific literature. However, a similar-in-phenotype orofacial pain perceived in the middle segment of the face has been described by few case series from mostly ear, nose and throat clinics. The authors of these descriptions used the term ‘midfacial segment pain’. Patients had no significant sinonasal disorder in these studies, but experienced symmetrical pain perceived mostly over the maxillary and ethmoid sinuses. No aura or autonomic symptoms were present apart from mild nasal congestion or rhinorrhoea in some individuals. This description appears similar to tension-type headache, but with midfacial location. In this viewpoint, we indicate a need to fill this gap in scientific knowledge and propose a multicentre interdisciplinary study that would give a detailed description of this type of orofacial pain.
The quest to systemically catalogue disorders causing facial pain is recent compared to its headache counterpart. Although headaches have had the recognition of three editions to date of the International Classification of Headache Disorders (ICHD-3) (1), facial pain only recently had its first document published as the International Classification of Orofacial Pain (ICOP-1) (2). It is understandable then that some disorders have yet to find their way to this document, especially in the case of problems located at the anatomical borders of the orofacial region or encountered by physicians other than neurologists or orofacial pain specialists. That is the case for a disorder known as the midfacial segment pain (midfacial pain) (MFSP) (3).
So far, this type of pain perceived in the middle segment of the face, has been mentioned by few case series from mostly ear, nose and throat clinics (3–5). In these studies, patients had no significant sinonasal disorder, but experienced symmetrical facial pain perceived over the maxillary and ethmoid sinuses. The results of paranasal sinus computed tomography and nasal endoscopic examination were normal. No aura, photophonophobia or nausea/vomiting was present during facial pain attacks, although some patients complained of nasal discharge and congestion. In other words, MFSP patients present with complaints of recurrent bilateral pain located below eyes, above lips and over the nose (Figure 1) without accompanying autonomic symptoms. The complaints are not secondary to any other disorder (e.g. rhinosinusitis or temporomandibular disorders). This description bears resemblance to tension-type headache (TTH) and persistent idiopathic orofacial pain (PIFP). However, it differs from the former by its midfacial location, and from the latter by paroxysmal non-daily occurrence. There are other similarities between MFSP and other primary and secondary facial pain disorders. For example, MFSP patients may describe facial hypersensitivity to touch, which could be the equivalent of myofascial tenderness (but not of the mastication muscles) or allodynia (4). Moreover, it is associated with significant burden (5), and may respond to prophylactic treatment with amitriptyline, carbamazepine, pregabalin, gabapentin or duloxetine (6).
Approximate midfacial segment pain location according to available descriptions.
There is some doubt whether MFSP is indeed a separate diagnosis. Some may suggest that it can be considered a subset of other disorders such as myofascial orofacial pain, PIFP or facial migraine. Conversely, we feel that temporal and anatomical features of MFSP differ significantly from these established diagnoses. MFSP phenotype appears to fit best the tension-type orofacial pain from among ICOP-1 diagnoses (2). However, tension-type orofacial pain is not supported by scientific descriptions published in available literature. Indeed, the search term ‘tension-type (oro)facial pain’ has been so far used only in review articles and studies on MFSP. It is our perception that MFSP represents the facial equivalent to the most prevalent headache in the general population: TTH. Furthermore, similar to the facial form of migraine, it merits recognition as a separate entity in the differential diagnoses of facial pain (6).
To substantiate this position, a multicentre interdisciplinary study is needed. The aim of such research should be to describe MFSP for the purposes of clinical application, education and research, with the ultimate goal to integrate MFSP in ICHD and ICOP.
Clinical implications
Midfacial segment pain is an equivalent to tension-type headache with orofacial distribution. We propose a study that will characterise this type of pain in multicentre and multidisciplinary setting.
