Lipohypertrophic Skin Changes in Patients With Diabetes: Visualization by Infrared Images

Many patients with diabetes on insulin therapy develop lipohypertrophies (LHTs). So far, LHTs are diagnosed by conventional methods (CM; visual inspection, palpation and/or ultrasound). In everyday life, it would be advantageous to have a quick, simple and inexpensive alternative, for example, diagnosing them by obtaining infrared (IR) images.

We obtained IR images from 43 subjects (21 patients with type 1 diabetes, conventional subcutaneous insulin therapy and known LHTs, 8 patients with CSII and LHTs, 7 patients without LHTs, and 7 healthy people), all from one specialized diabetes practice. The IR images were taken under standardized conditions with a high-resolution infrared camera (VarioCam® HDx Jenoptic, IR pixel 640 × 480, thermal resolution 0.003K) and compared with LHT diagnoses with CM.

In 14 of the 29 (48%) patients, CM diagnosed LHTs were "cold spots" in the IR images. The temperature difference to "healthy" skin (without LHTs) was up to 6°C. Of the 14 patients, 11 also showed such spots, without findings with CM. Four patients did not show clearly identifiable cold spots as LHT and 2 patients showed no changes in the IR images. The remaining 9 patients did not show clearly identifiable cold spots as LHT, but the diagnosis with CM was also ambiguous.

The results of this small (pilot) study do not clearly support the value of IR images for the diagnosis of LHTs, but they do not refute this approach. Diagnosis of LHT might be hampered due to the existence of different types of LHTs. Usage of IR images can apparently detect LHTs before they can be diagnosed with CM. Further targeted investigations are required to make statements about the usability of this method.