NICE vs SIGN: Management of Headache Disorders (2025) - A Clinical Comparison
This guide provides a detailed, factual comparison for UK clinicians between the National Institute for Health and Care Excellence (NICE) Headache guideline (NG217, published September 2021) and the Scottish Intercollegiate Guidelines Network (SIGN) guideline for the diagnosis and management of headache in adults (SIGN 155, published December 2018, with an addendum in 2021). While the SIGN guideline is older, its 2021 addendum ensures its COVID-19 and medication overuse headache (MOH) advice remains current. Understanding the nuances between these two authoritative sources is essential for effective, nation-wide consistent practice.
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Diagnosis and Assessment
Both guidelines emphasise the critical importance of accurate diagnosis, primarily using the International Classification of Headache Disorders (ICHD-3), and the need to identify "red flags" suggesting secondary headache.
NICE (NG217)
NICE adopts a highly structured, algorithmic approach to initial assessment. It provides a clear pathway starting with the identification of red flags, followed by a detailed headache history to determine the headache type.
- Structured Pathway: The guideline is built around a comprehensive flowchart, promoting systematic assessment to avoid missing serious causes.
- Focus on Red Flags: Provides a specific table of red flags (e.g., thunderclap headache, new-onset neurological deficit, headache with systemic illness) with clear actions (e.g., "refer immediately").
- Diagnostic Criteria: Strong emphasis on using ICHD-3 criteria for primary headaches (migraine, tension-type headache, cluster headache).
- Investigations: Advises against neuroimaging for patients with a clear history of migraine, tension-type headache, or cluster headache and no red flags.
SIGN (155)
SIGN also prioritises diagnosis based on clinical history and red flag identification but presents its guidance in a more discursive, narrative style alongside its recommendations.
- Clinical History Focus: Places significant weight on a detailed clinical history as the cornerstone of diagnosis. It includes a helpful "headache diary" recommendation to aid diagnosis and identify triggers.
- Red Flags: Similarly details red flags for secondary headache, aligning closely with NICE.
- Broader Diagnostic Context: Discusses the diagnosis of a wider range of secondary headache disorders in more detail within the main text.
- Neuroimaging: Concordant with NICE, it recommends against routine neuroimaging in the absence of red flags.
Key Difference: The main distinction is presentation. NICE offers a strict, flowchart-driven algorithm for diagnosis, ideal for quick reference in a busy clinic. SIGN provides a more detailed narrative on taking a history and considering differentials, which may be more beneficial for educational purposes or complex cases.
Pharmacological and Non-Pharmacological Treatment
Acute Migraine Treatment
Both guidelines recommend a stepped approach, starting with simple analgesics.
- NICE & SIGN: First-line: Aspirin (900mg) or an NSAID (e.g., ibuprofen) plus an anti-emetic if nausea/vomiting is present. Triptans are second-line if initial treatment fails.
- Key Difference - Triptans: NICE is more restrictive, stating offer a triptan only if aspirin/NSAID +/- anti-emetic is ineffective or contraindicated. SIGN suggests triptans can be considered alongside NSAIDs from the outset for moderate-to-severe attacks, reflecting a slightly more aggressive acute treatment stance.
Migraine Prophylaxis
This is an area of significant alignment, with both guidelines recommending prophylaxis based on attack frequency and impact.
- First-line: Both recommend propranolol (80-240mg daily) or topiramate (50-100mg daily) as first-line oral prophylactic agents.
- Key Advance - Anti-CGRP mAbs: NICE includes detailed recommendations for anti-CGRP monoclonal antibodies (erenumab, fremanezumab, galcanezumab) following TA869/TA909. They are recommended if at least three prior prophylactics have failed. SIGN's 2018 document predates NHS approval of these drugs, but the 2021 addendum acknowledges their existence and recommends clinicians refer to current NICE guidance, creating a de facto alignment.
- Non-Pharmacological: Both endorse acupuncture as a prophylactic option. NICE also specifically recommends a course of up to 10 sessions of acupuncture over a 5-8 week period.
Medication Overuse Headache (MOH)
Both guidelines agree on the core principle: educate patients about MOH and withdraw the overused medication.
- NICE: Provides a clear, directive pathway: advise complete cessation of the overused medication. For simple analgesics, this can be abrupt; for opioids, barbiturates, or benzodiazepines, a gradual withdrawal is advised. It emphasises that preventive treatments are less effective until the overuse is addressed.
- SIGN (2021 Addendum): The addendum provides crucial updated advice, strongly recommending early introduction or optimisation of preventive medication either just before or during withdrawal of the overused acute medication. This is a subtle but important practical shift towards a more supported withdrawal process.
Key Difference: The management of MOH withdrawal. NICE focuses on cessation first, then prevention. SIGN's updated guidance encourages initiating prevention concurrently with withdrawal, which may improve success rates and patient tolerance.
Special Situations and Patient Groups
Women of Childbearing Age and Pregnancy
- NICE: Has a dedicated section with specific recommendations. Advises caution with topiramate (teratogenic risk) and emphasises the need for highly effective contraception. For acute treatment in pregnancy, paracetamol is first-line.
- SIGN: Also covers this area thoroughly, with similar warnings on topiramate. Both guidelines are largely consistent in their cautious approach during pregnancy and breastfeeding.
Chronic Tension-Type Headache (CTTH)
- NICE: Recommends amitriptyline as the first-line prophylactic treatment (10-75mg daily), starting at a low dose.
- SIGN: Also recommends amitriptyline, demonstrating strong consensus on this point.
Practical Clinical Flow: A Synthesis
For a UK clinician, a practical, combined workflow can be derived from both guidelines:
- Assessment: Use a systematic approach (NICE's flowchart is excellent for this) to check for red flags. Take a detailed history, considering a headache diary (SIGN's suggestion).
- Diagnosis: Apply ICHD-3 criteria to diagnose the primary headache type.
- Acute Treatment: For migraine, start with an NSAID/aspirin +/- anti-emetic. Have a low threshold to add or switch to a triptan if attacks are severe or initial treatment fails (incorporating SIGN's pragmatic view).
- Prophylaxis: Consider if attacks are frequent or disabling. First-line: propranolol or topiramate (with caveats for women). For CTTH, use amitriptyline. For eligible patients with refractory migraine, refer for anti-CGRP mAb assessment per NICE.
- Manage MOH: If MOH is suspected, educate the patient and plan withdrawal. Strongly consider starting/optimising preventive medication alongside withdrawal, as per the updated SIGN addendum, for better outcomes.
Frequently Asked Questions (FAQs) for Clinicians
1. Which guideline should I follow in Scotland/Northern England?
While SIGN is produced in Scotland, its principles are universally applicable. In practice, there is very little substantive conflict. For the most up-to-date advice on newer treatments (e.g., anti-CGRP mAbs), NICE is the definitive source for the whole of the UK. Using the strengths of both—NICE's structure and SIGN's nuanced clinical advice—is a sensible approach.
2. How should I manage triptan non-responders?
Both guidelines suggest trying an alternative triptan if one fails. NICE specifically states that if oral triptans are ineffective or not tolerated, consider a non-oral formulation (e.g., nasal spray, subcutaneous injection). Review the diagnosis and consider MOH if multiple treatments fail.
3. What is the role of neuroimaging in a typical migraineur?
Both NICE and SIGN advise against routine neuroimaging in patients with a stable history of migraine that meets ICHD-3 criteria and has no red flags. Imaging is indicated only if the history is atypical or red flags are present.
4. A patient has MOH and failed several preventives. What next?
Address the MOH rigorously as per the withdrawal strategies above. Once the overuse is resolved, re-evaluate the need for prophylaxis. If the underlying migraine remains refractory and the patient meets criteria, they may be eligible for anti-CGRP monoclonal antibodies as per NICE TA869/TA909.
5. Are non-pharmacological treatments recommended?
Yes. Both guidelines support acupuncture for migraine prevention. They also stress the importance of patient education, lifestyle management, and identifying triggers. Cognitive behavioural therapy (CBT) may be considered for patients with significant anxiety related to their headaches.
Source Links
- NICE Guideline NG217 (Headaches in over 12s): NICE NG217
- SIGN Guideline 155 (Headache in adults): SIGN 155 (PDF)
- SIGN 155 2021 Addendum: SIGN 155 addendum (PDF)
- NICE Technology Appraisal TA869 (Erenumab etc.): NICE TA869