Red flags in ten minutes, a primary care view

The epidemiology is reassuring and the stakes are not. The overwhelming majority of headache presentations in general practice are primary headache disorders, most commonly migraine, and the serious secondary causes are rare. The difficulty is that the rare ones are catastrophic when missed, and the pressure that creates pushes in the direction of imaging and referring far more people than benefit from it.

The usual answer, and it holds up well, is a structured red-flag screen rather than clinical instinct alone.

SNNOOP10, briefly

The SNNOOP10 criteria collect the warning features associated with secondary headache into a single checklist. In compressed form:

• Systemic symptoms including fever
• Neoplasm history
• Neurological deficit, including altered consciousness
• Onset that is sudden or abrupt, the thunderclap presentation
• Older age at onset, generally over 50
• Pattern change, or a progressive headache in someone with a known headache disorder
• Plus positional headache, headache precipitated by sneezing, coughing or exercise, papilloedema, progressive headache with atypical presentation, pregnancy or puerperium, painful eye with autonomic features, post-traumatic onset, immune system compromise, and painkiller overuse or new drug at onset

Nobody recites that from memory in an appointment. What works in practice is a small number of habitual questions that cover most of it, and a low threshold for the two or three features that mean today rather than a routine referral.

The questions that carry the most weight

"How did it start?" asked so the patient describes the onset rather than the pain. Thunderclap onset is the highest-yield single feature and it is easy to lose in a description that begins with the last two weeks.

"Has anything about the pattern changed?" A known migraine patient whose headache has changed character deserves the same screen as a new presentation. Existing diagnoses are where secondary headaches hide.

"What are you taking for it, and on how many days?" This does two jobs. It screens for medication overuse, which is common and treatable, and it catches a new drug at onset. Expect the answer to be an underestimate and ask about over-the-counter medicines by name.

Positional and valsalva questions. Worse on standing, worse lying flat, brought on by coughing. These separate two patterns that behave differently and are both frequently missed, raised intracranial pressure and CSF hypotension.

Fundoscopy where the history suggests it. Papilloedema changes the pathway immediately. Idiopathic intracranial hypertension in particular is often carried for months as migraine.

The other half of the job

Excluding secondary headache is only the first task. The second, and the one that determines whether the patient comes back six times, is naming the primary disorder and starting a plan.

Two things make the largest difference and neither takes long:

Diagnose out loud. "This is migraine" is a clinical intervention. A large number of people with clear migraine have never been told they have it, and without a name there is no self-management, no useful reading, and no framework for what to try next.

Count before deciding. Headache days and treatment days per month determine almost everything downstream: whether prevention is indicated, whether medication overuse is in play, and whether the next appointment can measure anything. Asking a patient to bring counts to the follow-up converts a vague review into a decision.

Referral thresholds worth holding

Beyond the urgent features above, the pragmatic referral triggers in most UK pathways are consistent: diagnostic uncertainty after a proper history, failure of two or more adequately trialled preventives, chronic migraine being considered for specialist treatment, suspected cluster headache, and headache in pregnancy where treatment options need specialist input.

Cluster headache deserves particular mention. The diagnostic delay remains measured in years, and the presentation is distinctive enough that it should not be. Strictly unilateral, severe, orbital or temporal, lasting 15 to 180 minutes, with cranial autonomic features and restlessness rather than the wish to lie still. A patient pacing the room is not describing migraine.

Written for GPs and allied health professionals. It summarises widely used assessment frameworks and is not a substitute for local pathways or specialist advice. Erin Health is working towards Class IIa SaMD classification and CE marking under EU MDR 2017/745 and is not yet a certified medical device.