Cocaine affects the cutaneous system and other organ systems. Cocaine use is associated with vasculitides, infectious complications, and numerous dermatologic conditions. It has been associated with formication (ie, tactile hallucinations of insects crawling underneath the skin), which leads to delusions of parasitosis and other psychosis-related dermatologic disorders. When a patient presents to a dermatology clinic with chronic skin lesions, a vague medical history, negative findings from previous evaluations, labile affect, and delusional behavior, drug screening should be performed to identify possible cocaine use.