Thermal imaging and dermoscopy for detecting inflammation in frontal fibrosing alopecia
Frontal fibrosing alopecia (FFA) is an inflammatory condition of the scalp, which leads to scarring and slowly progressive recession of frontotemporal and/or frontoparietal hairline. Choice of FFA treatment is highly dependent on accurate assessment of disease phase, as medical treatments are effective only during the initial inflammatory stage.Methods
To objectively quantify the activity of the inflammatory process in FFA, 22 female patients were examined by both infrared thermography and optical dermoscopy before tissue sampling. The presence of perifollicular erythema or scaling was considered to be strongly suggestive for appropriate scalp biopsy site. Skin temperature differences in dermoscopy-selected area >0.5°C for temperature of the reference area (lower area of forehead) were considered abnormal. For evaluation of the inflammatory infiltrate, a grading scale was used.Results
The scale classified 14 (64%) subjects as being in the active disease phase of FFA and eight (36%) as in the inactive one. Using the thermography findings, 17 (77%) patients were considered to have the active FFA and five (23%) patients had the inactive one. The clinical assessment of active FFA was most accurate using thermal imaging combined with dermoscopy, with a sensitivity of 64%, a specificity of 88%, a positive predictive value of 90%, and an negative predictive value of 58%.Conclusion
We believe that infrared thermography is a noninvasive and accessible imaging modality that may serve as a complementary tool in FFA diagnosis.