<prompt> Magnans symptom, crack lung and crack dancing are seen in chronic use ofAlcholCanabisCocaineBarbiturates  <response>: Chronic use of cocaine The face will be pale, eyes sunken and marked evacuation, black discoloration of teeth and involuntary tooth grindingbruxism There may be persistent rhinitis nasal erosion with perforation Males suffer from loss of libido, impotence and infeility. Females suffer from galactorrhoea, amenorrhoea, and infeility. The person may suffer from paranoid or depressive psychosis, hallucinations, delusions, convulsions, and delirium due to degenerative changes in CNS The person may have tactile hallucination that insects are crawling under the skin. This is called Magnans symptom or Cocaine bugs formication. Crack lung refers to hypersensitivity, bronchospasm, dysnoea, and pneumonia occurs as a result of cocaine smoking. crack dancing refera to extra pyramidal signs and symptoms after cocaine intake. Ref: FORENSIC MEDICINE AND TOXICOLOGY Dr PC IGNATIUS THIRD EDITION PAGE 485 