Is the headache continuous?

Consider these red flags

Paraesthesia in face or head(Potential cervical hypermobility or instability)
<3/12 sudden onset with no reason & worsening symptoms
HA onset >50yrs of age – considered to be disease until proven otherwise, especially if migrainous in quality(Cranial Vasculitis – HA in temporal area with local symptoms)
>3/12 if sudden change in established Hx, especially if over 50yrs old
Sudden onset of vomiting (Tumour)
Headache with neck stiffness, fever & feeling unwell (Meningitis)
Distal pain following severe HA (Blood in the subarachnoid space/SAH)
Severe HA with pregnancy (Pre-eclampsia)
Consider recent trauma or recent surgery
Consider cord & VBI signs

Checklist for Cervicogenic Headache

Unilateral head or face pain without sideshift; the pain may occasionally be bilateral
Pain localised to the occipital, frontal, temporal or orbital regions
Moderate to severe pain intensity
Intermitten attacks of pain lasting hours to days, constant pain or constant pain with superimposed attacks of pain
Pain is generally deep and nonthrobbing, throbbing may occur when migraine attacks are superimposed
Head pain is triggered by neck movement, sustained or awkward neck postures; digital pressure to suboccipital, C2, C3 or C4 regions or over the greater occipital nerve; valsalva, cough or sneeze might also trigger pain
Restricted active and passive neck range of motion; neck stiffness
Associated signs and symptoms can be similar to typical migraine accompaniments including:
- nausea
- vomiting
- photophobia, phonophobia and dizziness
- others include ipsilateral blurred vision, lacrimation and conjunctival injection or ipsilateral neck, shoulder or arm pain