Ergotism is a condition caused by ingesting ergot, a fungus found on rye and some other grains. The fungi produce toxins with neurological and vascular effects, causing a variety of symptoms. Human populations have experienced ergotism for centuries and a number of historic records, particularly from the Middle Ages, document this condition. Improvements in agricultural practices have limited the risk of ergotism today; historically, the condition was a problem because people had limited food choices and in harsh winters, the only food available might be contaminated grain.
In the short term, exposure to ergot can cause hallucinations, mood disorders, vomiting, nausea, diarrhea, muscle twitching, and cramping. Some patients develop reddened skin and a burning sensation, explaining the alternate name “St. Anthony's Fire” used historically to describe this condition. Since many communities relied on single point sources for their grains, ergot contamination in the fields and mills could cause hundreds of people to become severely ill across a community.
Exposure to high volumes of ergot, especially over time, can cause chronic forms of ergotism. A neurological form is characterized by convulsions, twitching, and involuntary movements. Another form focused on the vascular system causes dry gangrene. The blood supply to the extremities is cut off as a result of extreme vasoconstriction, causing the limbs to die. Historically, the damaged limbs would turn black and fall off and this was depicted in gory, but informative, detail in a number of works of art.
It is possible that some populations actually used controlled dosages of ergot recreationally in religious rites and other proceedings. These communities believed that the hallucinations were a gift from god. This condition has also been pinpointed as the possible cause behind several recorded incidences of mass hysteria and some people have suggested that it may have been responsible for repeated incidents of witchhunts in communities in various regions of the world, as people began experiencing hallucinations, paranoia, and mood changes in response to ergot exposure.
The rarity of this condition makes it uncommon in medical offices. Treatments for ergotism can include the administration of vasodilators to prevent gangrene, along with nerve blocks for patients experiencing extreme neurological symptoms. Supportive care can also involve sedation for patients with behavioral outbursts. Once the fungus has been expelled from the patient's system, the treatment can be tapered off and the patient should make a complete recovery as long as no additional ergot is ingested.