Phenotype and Burden of a Midfacial Segment Pain

The study will include patients consulting rhinologic, oral medicine/dentistry, headache or pain specialists because of facial pain with the following features:

• located at least partially within an area innervated by the second or third division of the trigeminal nerve (both bilateral and unilateral)
• duration of attacks of > 5 minutes and \< 1 month
• attacks recur for > 1 month
• at least one pain-free day per month (this pain-free day must be unrelated to the use of abortive or prophylactic treatment modalities).

Exclusion criteria

1. Facial pain can be attributed to other ICOP-1 diagnosis, apart from tension-type orofacial pain. This means that investigators should exclude especially:

   • facial migraine by ensuring that facial pain is not accompanied by either migraine aura AND/OR nausea/vomiting AND/OR photo- and phonophobia
   • persistent idiopathic facial pain by ensuring that the patient experienced a pain-free day or days in the last month (this day or days must be unrelated to use of abortive or prophylactic treatment modalities).
   • stomatognathic disorders incl. myofascial orofacial pain (chapter 1-3 of ICOP-1) by ensuring that pain is neither unrelated to jaw motion, function or parafunction nor that signs of temporomandibular disorders are present on physical examination.
2. Facial pain with clear rhinogenic cause, such as acute and chronic rhinosinusitis fulfilling both clinical and endoscopic/imaging diagnostic criteria according to the European Position Paper on Rhinosinusitis and Nasal Polyps (EPOS 2020).
3. Facial pain that can be attributed to neoplasms.
4. Facial pain that can be attributed to local infection including post-herpetic neuralgia.
5. History of significant trauma associated with pain onset (pain developed within 7 days from trauma).

Patients who additionally and independently suffer from primary headaches whose mid-facial pain cannot be explained as orofacial headaches are explicitly not excluded. In other words, patients with migraine are not excluded, as long as their facial pain has no typical migraine features (i.e. nausea/vomiting, photo- AND phonophobia or aura) and facial pain attacks occur independently of headache episodes.

Also, patients showing signs of mucosal contact points or deviated nasal septum will be included, but the presence of these conditions should be noted in the patients' history. Moreover, patients with Lund-Mackay score of 4 or less can be included in the study, unless any singular sinus can be scored with 2 points.