Magnan's symptom is seen in?

Magnan's or cocaine bugs is characteristic of cocaine poisoning, in which there is a feeling as if grains of sand are lying under the skin or some small insects are creeping on the skin giving rise to itching sensation with resultant excoriation, leading to irregular scratches and ulcers.Ref: The Essentials of Forensic Medicine and Toxicology 29th Ed Page 545.