Thermographic analysis and autonomic response in the hands of patients with leprosy*

BACKGROUND Low temperatures and slow blood flow may result from peripheral neuropathy caused by leprosy, and the simple detection of cold fingers could already be a preliminary classification for these patients. OBJECTIVE To investigate whether infrared thermography would be able to measure this change in temperature in the hands of people with leprosy. METHOD The study assessed 17 leprosy patients who were under treatment at the National Reference Center for Sanitary Dermatology and Leprosy, Uberlândia/MG, and 15 people without leprosy for the control group. The infrared camera FLIR A325 and Therma CAM Researcher Professional 2.9 software were used to measure the temperature. The room was air-conditioned, maintaining the temperature at 25°C; the distance between the camera and the limb was 70 cm. The vasomotor reflex of patients was tested by a cold stress on the palm. RESULTS The study showed a significant interaction between the clinical form of leprosy and temperature, where the control group and the borderline-borderline form revealed a higher initial temperature, while borderline-lepromatous and lepromatous leprosy showed a lower temperature. Regarding vasomotor reflex, lepromatous leprosy patients were unable to recover the initial temperature after cold stress, while those with the borderline-tuberculoid form not only recovered but exceeded the initial temperature. CONCLUSION Thermography proved a potential tool to assist in the early detection of neuropathies, helping in the prevention of major nerve damage and the installation of deformities and disabilities that are characteristic of leprosy.