Disease, especially of the big toe, caused by an excess of uric acid in the blood (4)
I believe the answer is:
gout
(Other definitions for gout that I've seen before include "Disease causing inflammation, often of foot or toes" , "Painful inflammation of the foot" , "Painful (joint) ailment" , "Disease causing inflammation of toes and feet" , "Disease caused by excess uric acid in the bloodstream" .)