Alopecia is commonly seen in poisoning by
Copper
Mercury
Iodine
Thallium
Thallium may interfere with riboflavin homeostasis leading to dermatitis, alopecia, and neuropathy. Alopecia may also be seen in arsenic and lead poisoning Ref - Krishan Vij textbook of forensic medicine and toxicology 5e pg: 473
Poisoning