A system for determining a clinically relevant temperature differential between a predetermined area of interest on the body surface of a mammal and a control area on the body surface of said mammal, said system comprising: a visual and thermal image capturing device, said image capturing device comprising: a housing, a means for capturing a digital visual image within said housing and a means for capturing a digital thermal image within said housing a display apparatus, said display apparatus comprising means for showing said captured visual image and said captured thermal image and a computing apparatus, said computing apparatus operatively connected to said image capturing device and to said display apparatus, said computing apparatus comprising: a means for selecting a control area on the surface of the skin a means for determining an temperature of said control area a means for selecting an area of clinical interest within said visual image a means for calculating plane geometric features of said selected area of clinical interest a means for overlaying said digital image onto said thermal image in a desired orientation on said display apparatus and a means for applying a unique pixel value to a specific predetermined temperature range on said thermal image.