What causes paresthesias over the scalp?

Scalp Paresthesias: Causes and Diagnostic Approach

Primary Etiologies

Scalp paresthesias are most commonly caused by cervical spine disease, particularly degenerative disk disease at C5-C6, which creates chronic tension on pericranial muscles and scalp aponeurosis. 1

Cervical Spine Pathology (Most Common)

• Degenerative disk disease at C5-C6 is the predominant finding, present in 10 of 14 patients with scalp dysesthesia in one case series 1
• Associated cervical spine abnormalities include anterolisthesis, osteophytic spurring, lordosis, kyphosis, and nerve root impingement 1
• The mechanism involves chronic muscle tension transmitted to the scalp aponeurosis from underlying cervical pathology 1
• This represents a neuropathic phenomenon affecting peripheral nerve pathways 2

Small Fiber Neuropathy

• Diabetes mellitus is a significant risk factor for scalp dysesthesia through small-fiber neuropathy mechanisms 2
• Damage to peripheral pathways results in heightened nerve sensitivity and abnormal sensations disproportionate to external stimuli 2

Central Nervous System Lesions

• Trigeminal nerve pathology can cause facial and scalp paresthesias through compression, demyelination, or vascular abnormalities 3
• Multiple sclerosis causes demyelinating plaques affecting sensory pathways 2
• Stroke affecting sensory cortex or thalamus 2
• Tumors compressing sensory pathways 2

Post-Traumatic and Iatrogenic Causes

• Brow lift procedures can damage small sensory nerve fibers 2
• Keloid and burn scarring create localized neuropathic changes 2
• Trauma to scalp nerves (greater occipital, lesser occipital, auriculotemporal) 2

Metabolic and Systemic Causes

• Hypocalcemia from hypoparathyroidism causes perioral and acral paresthesias but can affect scalp 4
• Vitamin B12 deficiency causes subacute combined degeneration with sensory symptoms 4
• Post-infectious COVID-19 has emerging reports of associated scalp dysesthesias 2

Vascular Causes

• Giant cell arteritis presents with scalp tenderness and pain, requiring immediate ESR/CRP and temporal artery biopsy 3
• This is critical to exclude in elderly patients with scalp symptoms and systemic features 3

Critical Red Flags Requiring Urgent Evaluation

• Scalp tenderness with jaw claudication or pain in elderly patients mandates immediate ESR/CRP testing and temporal artery biopsy to exclude giant cell arteritis 3
• Acute onset with other cranial nerve involvement suggests skull base pathology requiring urgent MRI 5
• Progressive symptoms with neurologic deficits indicate possible neoplasm or demyelination 3

Diagnostic Algorithm

Initial Clinical Assessment

• Determine onset pattern: acute (<72 hours) versus gradual progression 6
• Assess for cervical spine symptoms: neck pain, limited range of motion, radicular symptoms 1
• Screen for diabetes mellitus and psychiatric history (both increase risk) 2
• Examine for scalp tenderness, jaw claudication (giant cell arteritis) 3
• Evaluate other cranial nerve function 5

Imaging Studies

• MRI of cervical spine is the primary diagnostic test for scalp dysesthesia, as 14 of 15 patients in one series had confirmed cervical spine disease 1
• MRI of brain with and without contrast if central lesion suspected (multiple sclerosis, stroke, tumor) 6
• CT temporal bone only if bony pathology suspected 3

Laboratory Testing

• ESR and CRP if giant cell arteritis suspected (elderly with scalp tenderness) 3
• Lyme serology in endemic areas 6
• Hemoglobin A1c for diabetes screening 2
• Vitamin B12 level if peripheral neuropathy suspected 4

Treatment Approach

First-Line Pharmacologic Management

• Gabapentin (oral or topical) is the primary treatment, with 4 of 7 followed patients showing improvement 1
• Pregabalin at low doses provides benefit for neuropathic scalp dysesthesia 7
• Topical compound of amitriptyline, lidocaine, and ketamine shows efficacy 7

Adjunctive Therapies

• Oral antihistamines and topical corticosteroids provide added value when combined with analgesic agents but are insufficient alone 7
• Address underlying cervical spine disease with physical therapy or orthopedic referral 1
• Optimize diabetes control if present 2

Common Pitfalls to Avoid

• Do not misdiagnose as seborrheic dermatitis, which is the most frequent misdiagnosis leading to failed standard dermatologic treatments 7
• Do not delay imaging in elderly patients with scalp tenderness—giant cell arteritis requires immediate treatment to prevent blindness 3
• Do not overlook cervical spine imaging, as this is the most common underlying cause 1
• Do not treat with topical corticosteroids or antihistamines alone—these require combination with neuropathic pain agents 7