Left-Sided Facial Warmth: Causes, Differential Diagnosis, and Red Flags

Potential Causes of Unilateral Facial Warmth/Sensation

Neurological

• Trigeminal neuralgia (TN): Paroxysmal, electric-shock pain in V2/V3 distribution; warmth/burning between attacks. Triggered by touch, chewing, cold.
• Trigeminal neuropathy: Post-herpetic, post-traumatic, tumor compression → constant burning, dysesthesia.
• Migraine with autonomic features: Unilateral facial flushing, warmth, lacrimation, nasal congestion during attacks.
• Cluster headache: Severe orbital/temporal pain + ipsilateral autonomic signs (flushing, sweating, ptosis, miosis).
• Transient ischemic attack (TIA)/stroke: Sudden sensory disturbance (warmth, numbness) ± other deficits. Act FAST.

Vascular

• Carotid artery dissection: Neck/facial pain, Horner’s syndrome, pulsatile tinnitus, stroke risk.
• Arteriovenous malformation (AVM): Pulsatile warmth, bruit.

Inflammatory/Infectious

• Sinusitis (maxillary): Pressure, warmth, pain over cheek; purulent discharge.
• Dental abscess: Referred warmth/pain to jaw, cheek; tooth sensitivity.
• Cellulitis: Spreading erythema, warmth, swelling, fever.
• Herpes zoster (pre-eruptive): Burning, allodynia in dermatome before rash.

Musculoskeletal

• TMJ disorder: Jaw pain, clicking, referred warmth to temple/cheek.

Other

• Autonomic dysfunction (e.g., Harlequin syndrome – unilateral flushing).
• Medication effect (niacin, calcium channel blockers).
• Anxiety/panic: Hyperventilation → peripheral vasodilation, warmth.

Red Flags – Seek Immediate Care

• Sudden onset + weakness, speech difficulty, vision loss → stroke.
• Severe headache “worst of life” → subarachnoid hemorrhage.
• Fever + progressive swelling → cellulitis/abscess.
• New facial asymmetry.

Workup

History, cranial nerve exam, neurovascular assessment → MRI/MRA brain/neck, CT sinus, dental eval, ESR/CRP as indicated.