Uric acid is a breakdown product of proteins. It is raised because of over production or more frequently from poor kidney excretion. Above this uric acid crystal deposits in cartilage and joint tissues.
Crystals occur in the urine as gravel or stones.
The red dust is like blood. The inflamed joint is purpley-red, swollen, shiny with peeling of the overlying skin. The weight of bed clothes or jarring by someone walking nearby causes agonizing pain. Pain lasts for days or until effective treatment. About a third have had preceding kidney back pain.