Table 2 Criteria for determining causal relationship between associated pathology and headache

1.

Close temporal relationship between the associated disease and the onset of pain

2.

Side concordance between the unilateral pain and the lesion, if localized

3.

Surgical remission, if the patient was operated on, or prompt remission after aetiological medical therapy, if indicated, without the need of constant indomethacin administration

4.

Prolonged post-treatment follow-up, in order to exclude a relapse of the headache attacks or improvement due to spontaneous remission