Via Volokh, an article to drive a hypochondriac crazy:
What Your Body Is Telling You
Brittle Nails, Spider Veins and Other Seemingly Innocent Oddities Could Signal Serious Trouble — or Not
Eyebrows that no longer extend over the corners of the eyes can indicate an underactive thyroid, and a diagonal crease in the earlobe seems to herald a heightened risk of heart attack.
Or perhaps you tweezed too much and slept on the wrong side of the pillow crease?
If you go to the article, there’s also this odd symptom,
subtle clues like losing hair on the toes
What if you never had hair on your toes? Not being a hobbit, I’ve had hairless toes all my life.