Painful trigeminal neuropathy (PTN) or trigeminal neuropathic pain can be caused by an external traumatic event (painful post-traumatic trigeminal neuropathy, previous name: anaesthesia dolorosa), other factors known to be able to cause trigeminal neuropathy (PTN attributed to other disorder), or without known aetiology (idiopathic PTN). The International Classification of Headache Disorders, third edition (ICHD-3) demands plausible neuroanatomical evidence for trigeminal neuropathy, and clinical signs of loss or gain of function for PTN. The first edition of the International Classification of Orofacial Pain (ICOP-I) includes confirmatory test evidence for PTN diagnosis, in addition to clinical signs; without confirmatory test results PTN remains probable. Confirmatory diagnostic tests include psychophysical and neurophysiological recordings, structural imaging, and skin biopsy. They are invaluable in PTN diagnostics, especially at the chronic stage when symptoms and signs may spread outside the original distribution, and clinical sensory examination may remain inconclusive because of its poor diagnostic value. Treatment for PTN consists of standard neuropathic pain medications and therapeutic neuromodulation techniques.