Headache caused by reversible cerebral vasoconstriction syndrome (RCVS) and persisting for more than 3 months after onset.

Diagnostic criteria:
  1. Headache previously diagnosed as Acute headache attributed to reversible cerebral vasoconstriction syndrome (RCVS) and fulfilling criterion C
  2. Normalization of cerebral arteries, shown by follow-up indirect or direct angiography, within 3 months of onset of RCVS
  3. Headache has persisted for >3 months after its onset
  4. Not better accounted for by another ICHD-3 diagnosis.

A few studies have documented headaches meeting the criteria for Persistent headache attributed to past reversible cerebral vasoconstriction syndrome. Research is needed to identify risk factors for such persistent headache; a previous history of 1. Migraine may play a role, as may anxiety/depression.