What are the key clinical features that differentiate trigeminal neuralgia from other causes of facial pain?

Key clinical features that differentiate trigeminal neuralgia (TN) from other causes of facial pain include:

• Paroxysmal, unilateral facial pain: TN typically presents as sudden, brief, electric shock-like or stabbing pain episodes localized to one or more divisions of the trigeminal nerve, often triggered by light touch or activities such as chewing or talking NICE NG127 Türp & Gobetti 1996.
• Trigger zones: The pain is characteristically triggered by touching specific areas on the face, which is a hallmark feature distinguishing TN from other facial pain syndromes NICE NG127.
• Absence of persistent numbness or neurological deficits: Unlike other causes of facial pain associated with persistent facial numbness or abnormal neurological signs, TN usually does not present with continuous sensory loss; if such signs are present, alternative diagnoses or secondary causes should be considered and neuroimaging is recommended NICE NG127.
• Duration and pattern of pain: TN pain attacks are typically very brief, lasting seconds to a few minutes, and can recur multiple times daily, whereas other facial pain causes such as atypical facial pain or migraine-related facial pain tend to be more constant or longer-lasting Türp & Gobetti 1996.
• Response to carbamazepine: TN often shows a good initial response to carbamazepine, which is less typical for other facial pain disorders NICE CG173.
• Absence of autonomic symptoms: Unlike trigeminal autonomic cephalalgias (TACs) such as cluster headache or SUNCT/SUNA, TN does not usually present with prominent ipsilateral autonomic features like lacrimation, nasal congestion, or eyelid swelling VanderPluym & Richer 2015.

In summary, the key differentiators of trigeminal neuralgia are its unilateral, brief, shock-like pain triggered by facial stimulation without persistent sensory loss or autonomic symptoms, and its typical response to carbamazepine treatment. Other facial pain causes often have different pain qualities, durations, associated neurological signs, or autonomic features NICE NG127,NICE CG173 Türp & Gobetti 1996VanderPluym & Richer 2015.