Quantitation of thyroid hormone effect on skin perfusion by laser Doppler flowmetry

Clinical observations have long suggested that skin perfusion (SP), among other factors, depends on thyroid status. However, quantitative data concerning this relationship are rather sparse. This study char-acterizes SP by means of laser Doppler flowmetry (LDF) in various thyroid dysfunctional states. The data reveal that mean capillary flow velocity, capillary pulse wave amplitude, and capillary flow oscillation amplitude, but not capillary flow oscillation frequency, are increased in hyperthyroid patients and decreased in hypothyroid patients. Regaining the euthyroid state is accompanied by normalization of LDF parameters only in hyperthyroid patients. It is concluded that LDF is useful in monitoring the thyroid effect on SP. However, it may not be used as a biological marker for the thyroid status of a given individual.