Alopecia is commonly seen in poisoning by
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
Copper
Mercury
Iodine
Thallium
Poisoning