Constant, unilateral pain in the distribution of the ophthalmic division of the trigeminal nerve, sometimes extending to the maxillary division, accompanied by ipsilateral Horner’s syndrome and caused by a disorder in the middle cranial fossa or of the carotid artery.

Diagnostic criteria:
  1. Constant, unilateral headache fulfilling criterion C
  2. Ipsilateral Horner’s syndrome, with imaging evidence of underlying disease of either the middle cranial fossa or the ipsilateral carotid artery
  3. Evidence of causation demonstrated by both of the following:
      1. headache has developed in temporal relation to the onset of the underlying disorder, or led to its discovery
      2. headache has either or both of the following features:
        • a) localized to the distribution of the ophthalmic division of the trigeminal nerve, with or without spread to the maxillary division
        • b) aggravated by eye movement
  4. Not better accounted for by another ICHD-3 diagnosis.

The original description of 13.9 Paratrigeminal oculosympathetic (Raeder’s) syndrome is regarded as a classical example of clinico-anatomical methodology in the early 20th century, and was useful because the involvement of oculopupillary sympathetic fibres indicated a lesion of the middle cranial fossa. Whether the term Raeder’s syndrome should be used today is heavily debated, but painful Horner’s syndrome is still considered by some authors to be a diagnostically useful indication of a middle cranial fossa lesion or of carotid artery dissection.