Gout is the concentration of uric acid crystals around the joints causing a painful condition. Chameleons will often develop gout around their “ankles” and legs with have a swollen appearance. The painful nature of it will make using the limb difficult. At this time it is unclear what causes the gout, though it is suspected to be dietary.
Suspect gout if your chameleon’s ankles start to have a rounder than usual or swollen appearance. Any show of discomfort when using the foot to grasp a perch is a sign of a progressing case of gout. As the gout can be subtle to begin with, take note of any difficulty hanging onto the branch. Metabolic Bone Disease will result in feet being too weak to grab a branch, while gout is it being too painful to grab the branch tightly. It is important to determine which one it is before embarking on a treatment plan!
The vet will have approaches to try to reduce the gout. This is worth going in to address as gout is painful for your chameleon and they will eventually just not want to use their limbs.