What Causes Pain And Swelling On Thumb?

My husband has a huge swollen thumb not sure why. This was noticed a few day ago. . . it is warm to the touch 2 times larger than the other and painful. When he touches it it stays red and does not turn white at all. He has been working with some black mold on a home basement remodal. We have soaked it in Epson salt and started him on Augmenton just what we had in the cabinet and Ibuprofen. When should we be concerned? And is there any homeopathic remedy we could try? what about gout???