Validation of a protocol for the assessment of skin temperature and blood flow in childhood localised scleroderma

Background/purpose: Localised scleroderma (LS) is the most common form of scleroderma seen in children, and usually presents unilaterally. Infrared thermography (IRT) and laser Doppler (LD) have both been reported to be useful in assessing the active, inflammatory stage of LS. We developed and validated a protocol using these techniques for the assessment of unilateral LS activity in children. Method: We investigated the spatial variability and repeatability of LD measurements from adult control forearm skin, and the inter- and intra-operator reproducibility of both LD blood flow trace analysis and IRT skin temperature analysis. Software was developed to produce overlay images of thermograms onto digital photographs of skin sites. In a group of seven adult control subjects, we established the normal range for skin temperature and LD blood flow at six standardised sites (forehead, cheek, abdomen, back, arm and leg), and measured contralateral differences in readings. In a group of 34 children with LS, we investigated the skin temperature and LD blood flow in unaffected skin at the same six sites. Results: In adults, physiological variability inLD blood flow and skin temperature between the two sides of the body was found to be greater than the uncertainty introduced into the measurements by (inter alia) limited intra- or inter-operator reproducibility. The cheek displayed the highest mean asymmetry in both skin temperature (0.5°C) and LD blood flow (40%). Conclusion: Our protocol combines IRT, LD and photography for LS assessment in children, and establishes a normal range of readings in line with other authors.