The Infra-Red Thermometer in Podiatry

The infra-red thermometer has established itself as an essential instrument in podiatry, offering clinicians a quick, non-contact method to measure a patient's skin temperature.

Use During Health Crises

During outbreaks such as SARS and Covid-19, infra-red thermometers became standard tools for screening travellers and visitors at borders and entrances. Forehead temperature checks were used to detect potential infections, with those showing elevated readings being isolated as a precaution.

Clinical Significance of Temperature

In medical practice, four major signs indicate inflammation: redness, swelling, impaired function, and heat. A rise in skin temperature may signal infection, whether it is local or systemic. Infra-red thermometers allow podiatrists to rapidly identify areas of concern and possible infection.

Role in Diabetic Foot Medicine

Infra-red thermometry has long been valued in diabetic foot care, particularly in detecting Charcot neuroarthropathy. Landmark studies by Armstrong et al in 1996* and 1997** highlight its significance, and more recent research in 2021+ explores its use in monitoring wound healing.

To assess a potential Charcot foot, clinicians measure temperature at a specific point—commonly the dorsum—on both feet. If the affected foot is at least 4°C warmer than the other, Charcot neuroarthropathy is suspected. A definitive diagnosis is made through further imaging, such as bone scans.

Home Monitoring in Diabetes

Beyond clinical settings, infra-red thermometry has proven beneficial for home monitoring, especially for diabetic patients recovering from foot ulcers. Various American studies show that regular temperature checks at home enable earlier detection of symptoms, allowing timely intervention before ulcers or Charcot foot progress.

Normal Foot Temperatures

Ordinarily, foot temperatures range from 29°C at the arch to 26°C at the toes, although the difference between these areas may be as much as 7°C+. What matters most, however, is symmetry: both feet should display similar temperature patterns. When evaluating for infection, clinicians focus on areas showing higher temperatures compared to surrounding tissue.

In summary,

Infra-red thermometers are invaluable clinical tools for podiatrists. While a single elevated temperature reading alone does not confirm a diagnosis, it provides vital symptomatic evidence. Extending thermometry to home use—where patients record daily readings at designated points—creates an early warning system, improving outcomes for both patients and clinicians.

*David G. Armstrong, Lawrence A. Lavery, Monitoring neuropathic ulcer healing with infrared dermal thermometry. The Journal of Foot and Ankle Surgery, Volume 35, Issue 4, 1996.

**David G Armstrong, Lawrence A Lavery, Paul J Liswood, William F Todd, Jeffrey A Tredwell, Infrared Dermal Thermometry for the High-Risk Diabetic Foot, Physical Therapy, Volume 77, Issue 2, 1 February 1997

+A Ghosh, S. Ray, MK Garg, S Chowdhury, S Mukhopadhyay. The role of infrared dermal thermometry in the management of neuropathic diabetic foot ulcers. Diabetic Medicine 2020

++ Thermographic Diabetic Foot Assessment in Podiatric Practice. Peter Plassmann. Poster presentation International Symposium of the Diabetic Foot. 2023