Narrow-band reflectance spectrophotometry and infrared thermography for assessment of skin lesions in localized scleroderma.

Abstract

Infrared thermography (IRT) is a useful method to detect activity/inflammation in localized scleroderma (LoS); however, inactive skin lesions with a severe degree of dermal and subcutaneous atrophy may show false-positive results. Narrow-band reflectance spectrophotometry (NBRS) is an objective, non-invasive technique of measuring erythema and hyperpigmentation severity, yet has not been extensively studied in LoS. The aim of this research was to compare the spectrophotometric results with thermographic examination of LoS lesions. The lesions were assessed using the Localized Scleroderma Assessment Tool (LoSCAT), Dyspigmentation, Induration, Erythema, and Telangiectasias (DIET) score, NBRS and IRT. The difference in the erythema index (ΔEI), melanin index (ΔMI) and average temperature Tavg (ΔTavg) were calculated between each lesion and its normal control. Fifty-five patients with 49 active and 64 inactive LoS lesions were examined. The ΔEI strongly correlated with the erythema (rs = 0.62, P < 0.0000002) and DIET score (rs = 0.66, P < 0.0000001) and moderately correlated with the telangiectasias score (rs = 0.58, P < 0.00001). ΔMI showed strong correlation with the dyspigmentation score (rs = 0.65, P < 0.0000001). There was a strong correlation between the ΔTavg and the erythema score (rs = 0.7, P < 0.000001). A moderate correlation between the Δ EI and ΔTavg was found in active LoS lesions (rs = 0.53, P < 0.0001). Narrow-band reflectance spectrophotometry may be a complementary method for determining erythema in LoS active lesions, although this technique remains inferior to IRT, because is unable to distinct between active and inactive lesions. However, NBRS enables to evaluate the severity of hyperpigmentation and telangiectasias, and it can be useful for the assessment of disease severity which is poorly evaluated by IRT.