CHANGES in the skin as a result of disease of the trigeminal nerve have rarely been reported. Most such lesions followed surgical section of this nerve or injections in its peripheral pathway for the relief of tic douloureux. Karnosh and Scherb1 reported an eczematous eruption in the distribution of the first and second divisions following section of these branches. Harris2 stated that superficial ulcerations at the ala nasi, and more rarely on the cheek and forehead, follow injections of alcohol into the gasserian ganglion in a small percentage of cases. Schornstein3 reported 8 cases of progressive ulceration, commencing at the ala nasi, subsequent to retroganglionic section and injection of alcohol into the ganglion. Necrosis of the maxillary mucous membrane occurring twelve years after a retrogasserian neurectomy was recorded by Dechaume and Delibéros.4 They stated that an ill fitting denture was the probable precipitating cause. Three cases