The International Classification of Headache Disorders (ICHD) criteria for THS include the following:7
A.	Unilateral headache fulfilling criterion C
B.	Both of the following:
	1. granulomatous inflammation of the cavernous sinus, superior orbital fissure or orbit, demonstrated by MRI or biopsy
	2. paresis of one or more of the ipsilateral IIIrd, IVth, and/or VIth cranial nerves
C.	Evidence of causation demonstrated by both of the following:
	1. headache has preceded paresis of the IIIrd, IVth, and/or VIth nerves by ≤2 weeks, or developed with it
	2. headache is localized around the ipsilateral brow and eye
D.	Not better accounted for by another ICHD-3 diagnosis.