MERALGIA PARAESTHETICA, A RARE CAUSE OF C IRCUMSCRIBED ALOPECIA

History and clinical findings: Two patients with circumscribed alopeci a on the lateral aspect of the thigh underwent a neurological investig ation after medical and dermatological examinations had failed to esta blish the cause. Patient 1 also had neuralgia of the genitofemoral ner ve after osteotomy of the iliac crest; patient 2 had insulin-dependent diabetes mellitus, Within the affected part of the skin both patients had sensory dysfunctions over the area of distribution of the cutaneo us lateral femoral nerve. Patient 2 additionally had sensory dysfuncti ons in other areas of innervation. Investigations: Neurogram and recor dings of sensory evoked potentials revealed decreased amplitudes on th e affected side, establishing the diagnosis of meralgia paraesthetica. Treatment and course: The painful neuropathy was successfully treated in both patients with carbamazepine (patient 1: 1.600 mg daily; patie nt 2: 900 mg daily). Conclusion: Circumscribed alopecia can be caused by peripheral nerve lesions. It should be considered in the differenti al diagnosis, particularly as the cause can be easily established.