Does the skin heat up before it breaks down in diabetic foot ulceration?

Most diabetic foot ulcers are caused by tissue stress from being ambulatory in people without protective sensation. These ulcers are suggested to be preceded by local skin temperature increase due to inflammation of the underlying tissue, a so-called hotspot. Evidence to support this mechanism of ulcer development is meagre at best. We investigated if foot ulcers are preceded by increased skin temperature in people with diabetes and foot ulcer history.

Participants measured temperature at 6-8 plantar foot locations each day for 18 months and identified a hotspot with a temperature difference >2.2°C between corresponding foot locations for two consecutive days.

Twenty-nine of 151 participants developed a non-traumatic ulcer while adhering to temperature measurements. In the 2 months prior to ulceration, 8 (28%) had a true hotspot (i.e. at/adjacent to the ulcer location) and the hotspot was on average no longer present 9 days before ulceration. Seven (24%) participants had a false hotspot (i.e. at another location) and 14 (48%) had no hotspot.

The skin of the majority of the ulcers does not heat up before it breaks down or, when it does, not directly before breakdown, questioning the foot temperature increase-uslcer association.