Definitely a head-scratcher!!! A few questions....

Anything happen 10 years ago when this started? Anything else medical going on (i.e. circulatory disorders.....)? What have you found in your assessment.....what have you assessed?

Is the burning along a specific path. i.e. does it along the distribution of a specific peripheral nerve??? (or dermatome for that matter?)

Does he get swelling in hot climates? Could effusion be putting compression on a peripheral nerve???