In the Middle Ages, they seem to have some colorful terms for modern diseases. Things like 'joint evil' (arthritis) and bloody flux (dysentery) are obvious, but the one that I can't find any substantive sources about is called 'Arnaldia'. Apparently both King Philip II of France and Richard I of England came down with it, and both lost their nails and hair... Phillip's hair didn't come back, but Richard's did.
What is this mystery ailment? I've heard some people claim it may have been scurvy, but I'm not convinced... Also malaria is supposedly sometimes mentioned but Richard is known to have recurring bouts of that already and it was called something different.
Are there any sources at all that shed any light on what Arnaldia might have been in terms of modern medical parlance?
Most likely we're looking for a disease affecting the fingernails, so we can go straight to the proper prefix in our search: Onycho-. From here there's 3 nail conditions which fit criteria: Onycholysis, Onychoptosis defluvium, and Onychomadesis. There's a start.
Onycholysis isn't necessarily a full loss of fingernails but a separation from the nail bed which can lead to full fingernail loss. Some of the common causes are Hyperthyroidism and Iron Deficiency.
Hyperthyroidism is also associated with brittle, drying hair or hair loss, as well as many other maladies. It's usually caused by deficiency in diet with respect to Iodine levels. Both being campaigning crusaders, dietary deficiency is definitely within the realm of possiblity.
Iron Deficiency is also dietary and falls in the same category of possibility. Along with hair loss and brittle nails, it also comes with a wide range of semi-common nutritional maladies.
Onychoptosis defluvium is associated with Alopecia areata in which select or all areas of hair/nail growths fall out. It usually doesn't carry many other symptoms beyond the psychological stresses of losing one's hair. The hair can also regrow later, consistent with Richard's regrowth. This disease is especially interesting because it's pretty widely considered to be genetic and these two men share at least one ancestor I can think of off the top of my head in William the Conqueror.
Finally, the catch-all term we would use for this phenomena: Onychomadesis. Basically the nails stop growing for an unknown reason. It's not generally associated with any other symptoms in adults. Plausible but unlikely.
What any of these diseases were called historically, or when they were first identified, I couldn't tell you.
Arnaldia seems to share many symptoms with oropharyngeal tularemia. High fever lasting 1-2 weeks, mouth ulcers, sore throat, headache, debilitation. It can be caused by consuming contaminated food and/or water. More information is available on the Mayo Clinic website under Tularemia.
doesnt radiation poisoning cause the hair to fall out?