Are autoimmune diseases a modern phenomenon?
Autoimmune diseases / defects such as allergies, neurodermitis, asthma, Crohn's disease, etc. are are commonly perceived as "modern" diseases having "appeared" some time in the latter half of the 20th century.
There is a popular notion that "when we used to play in the mud", people were generally healthier and linking the prevalence of autoimmune diseases to modern sanitary standards. I have recently read about the theory that autoimmune diseases are essentially caused by the "loss" of parasites of all kinds living with humans. Other popularly assumed causes include industrial waste and exhaust, exposure to processed chemicals and "superprocessed" food.
On the other hand, I presume that people may have simply suffered and died more or less silently from autoimmune diseases undiagnosed for lack of modern methods of diagnostics.
However, I am not aware of any scientific or historical documentation in support of these concepts, while I am aware that for example many psychiological illnesses were simply not systematically diagnosed before the rise of modern, evidence-based medicine starting around 1900.