Dear Doctor,

As you know, diabetic neuropathy is a major contributory factor in the causation of foot ulcers in people with diabetes. It is not only the “loss of the gift of pain” as a result of sensory neuropathy, but patients also have peripheral autonomic (sympathetic) neuropathy that leads to a warm foot (in the absence of significant peripheral arterial disease) and a dry foot.

Sweating is controlled by the sympathetic nervous system. This is lost in the high risk diabetic foot leading to excessive dry skin which can increase callous formation and focal areas of presssure leading to an ulceration.

Neuropad® has been used for many years in European settings as this is a simple sweat test and change of color from blue to pink indicates normal sweating. The patient with a high-risk diabetic foot and absence of sweating will not see any change in the color of the applied Neuropad. Therefore, this is a very helpful marker of autonomic neuropathy in the foot which leads to increased risk. An additional benefit of this is that it can be used as a visual aid to better educate patients as to their risk for developing life-threatening lower extremity complications.

You might find the prospective observational study by Panagoulias G et al to be interesting (Panagoulias G et al, Frontiers in Endocrinology 2020; 11).

Sincerely,

Andrew JM Boulton, MD, DSc, FACP, FRCP
Professor of Medicine, University of Manchester
Consultant Physician, Manchester Royal Infirmary
Manchester, UK
Visiting Professor of Medicine,
University of Miami, Miami, FL, USA