Mnemonic SNOOP helps to identify red flags in patients presenting with headaches.

SNOOP helps clinicians recognize warning signs that a headache may be secondary to a serious underlying condition.

S stands for Systemic symptoms or secondary risk factors such as fever, weight loss, history of cancer, or HIV, which raise concern for infection or malignancy.

N stands for Neurological symptoms including confusion, altered mental status, focal deficits, or seizures, suggesting possible stroke, mass lesion, or encephalitis.

O refers to Onset that is sudden or thunderclap in nature, reaching peak intensity within seconds, which may indicate subarachnoid haemorrhage.

The second O is Onset after age 50, where a new headache in an older adult could point to temporal arteritis, mass, or vascular pathology.

P is for Pattern change or Progressive headache, such as the first or worst headache ever, increasing frequency or severity, poor response to usual treatments, or headaches triggered by exertion or Valsalva manoeuvre, all of which could suggest a brain tumor, bleed, or cerebrospinal fluid pressure abnormality.

If any SNOOP features are present, further evaluation including neuroimaging or further specialist

referral is advised.