Hi,
Do you know how old the lizard is? When you handle it how long is it for and do you let the beardie roam on the floor or just hold it?
Its very unusual for a beardie to be that aggressive, usually they get tamer with handling not more aggressive, my only thought is there may be something in the handling that irritates it. Depending on the age it may also be going through "the terrible two's" in beardie age where they approach sexual maturity and can become slightly grumpy.
Would you mind roughly describing the enclosure including temperatures and how you measure them just in case is something to do with husbandry.
Although its probably something really simple, there are one or two dragons out there that are just moody!
