I have a throbbing left‑sided headache that occurs when I comb my hair; what could be causing it and how should I treat it?

Left-Sided Throbbing Headache Triggered by Combing Hair

Your headache triggered by combing your hair most likely represents either external compression headache from direct scalp pressure or allodynia (scalp tenderness) associated with an underlying primary headache disorder such as migraine or tension-type headache.

Most Likely Diagnoses

External Compression Headache

• Direct mechanical stimulation of cutaneous nerves during combing can trigger localized headache pain that is constant and more severe at the site of pressure application. 1
• The pain mechanism involves compression of trigeminal or occipital nerve branches in the scalp, which resolves after the pressure stimulus is removed. 1
• In predisposed patients with migraine, prolonged external compression can trigger a more severe migrainous headache. 1

Migraine with Cutaneous Allodynia

• Migraine commonly presents with unilateral, throbbing pain and can cause scalp tenderness (allodynia) that makes routine activities like hair combing painful. 2
• Migrainous headache is characterized by moderate-to-severe throbbing pain, often unilateral, with photophobia, phonophobia, and nausea. 3
• The throbbing quality and unilateral location you describe are classic migraine features. 2

Myofascial Trigger Points

• Active trigger points in the temporalis muscle can produce referred pain to the temple and behind the eye with local scalp tenderness that is aggravated by touch or pressure. 4
• Patients with chronic tension-type headache show significantly higher local pain intensity and larger pain areas when temporalis trigger points are stimulated. 4

Red Flags Requiring Urgent Evaluation

You need immediate medical evaluation if any of these features develop:

• Thunderclap onset (sudden severe headache reaching maximum intensity within seconds to minutes) suggests subarachnoid hemorrhage and requires immediate non-contrast CT. 5
• New focal neurological symptoms (weakness, numbness, vision changes, speech difficulty) suggest stroke, tumor, or increased intracranial pressure. 2, 3
• Fever with neck stiffness suggests meningitis and requires immediate evaluation. 3
• Progressive worsening over days to weeks with papilledema could indicate cerebral venous thrombosis or idiopathic intracranial hypertension. 2
• Scalp edema or dilated scalp veins may indicate superior sagittal sinus thrombosis. 2

Recommended Evaluation

Clinical Assessment

• Examine for scalp tenderness, trigger points in temporalis muscles, and any localized areas of allodynia to distinguish between external compression, myofascial pain, and migraine-related allodynia. 4
• Assess headache characteristics: duration, frequency, associated symptoms (nausea, photophobia, phonophobia), and temporal pattern to differentiate migraine from tension-type headache. 2, 6
• Perform a complete neurological examination including cranial nerves, motor/sensory function, and fundoscopy to exclude secondary causes. 3

When Neuroimaging Is Indicated

• Neuroimaging is NOT routinely needed for typical primary headache patterns without red flags. 2
• Consider MRI brain if you have unexplained neurological findings, progressively worsening headache, or headache that awakens you from sleep. 2
• MRI with MR venography should be obtained if cerebral venous thrombosis is suspected (progressive headache over days/weeks, risk factors like oral contraceptives). 5

Treatment Approach

For Acute Episodes

First-line treatment:

• Start with NSAIDs (ibuprofen 400-600mg, naproxen 500-550mg, or diclofenac potassium 50mg) as first-line acute therapy. 2
• Avoid combing or manipulating the affected scalp area during acute episodes to prevent triggering or worsening pain. 1

Second-line treatment if NSAIDs fail:

• Triptans (e.g., sumatriptan 50-100mg) should be used when NSAIDs provide inadequate relief, taken early when headache is still mild. 2
• Triptans are contraindicated if you have coronary artery disease, uncontrolled hypertension, or history of stroke. 7

Preventive Strategies

If headaches occur more than twice weekly:

• Preventive therapy should be considered to avoid medication overuse headache, which develops when acute medications are used more than 2 days per week or 10 days per month. 2
• For migraine prevention, options include topiramate, beta-blockers, or tricyclic antidepressants (though weight gain with some agents should be considered). 2
• Lifestyle modifications including regular sleep, adequate hydration, regular meals, and stress management can reduce headache frequency. 2

Physical Interventions

• If myofascial trigger points are identified, physical therapy focusing on trigger point release and posture correction may provide benefit. 3
• Avoid tight headwear, hair accessories, or hairstyles that create sustained scalp pressure. 1

Critical Pitfalls to Avoid

• Do not dismiss unilateral headache with scalp tenderness as benign without excluding secondary causes if red flags are present. 5
• Do not use acute headache medications more than 2 days per week, as this leads to medication overuse headache requiring detoxification. 7, 2
• Do not assume all scalp pain is external compression—consider that scalp allodynia may indicate an underlying migraine disorder requiring specific treatment. 2
• Do not delay neuroimaging if the headache pattern changes, becomes progressively worse, or develops new associated symptoms. 2