Blood flow in psoriatic skin lesions: the effect of treatment

Laser Doppler velocimetry (LDV) was used to assess the effect of treatment upon cutaneous blood flow in psoriatic skin lesions. The resolution of two separate plaques in each of seven subjects was followed. Six of the subjects received the Goeckerman regimen, the seventh was reated with psoralen‐ultraviolet A (PUVA) therapy. Control LDV readings were taken from uninvolved skin sites during the treatment period. Cutaneous blood flow in the psoriatic lesions of the Goeckerman‐treated patients decreased to levels comparable to those in uninvolved skin early in the course of treatment and significantly preceeded the observed clinical resolution from 4 to 8 days after initiation of therapy (P < 0.05). Visible flare‐ups sometimes appeared when patients were untreated (over a weekend, for example) and these eruptions were accompanied by a transient elevation of LDV readings. Perfusion of the lesions of the PUVA‐treated patient remained consistently higher than perfusion of uninvolved skin despite clinical healing. In a separate series of experiments, blood flow at the extensor surface of the forearm was measured in the skin of normal subjects, the uninvolved skin of psoriatic patients and the untreated lesional skin of psoriatic patients. While the lesional skin had significantly higher perfusion levels than uninvolved psoriatic or normal control skin (P < 0.01), there was no significant difference between blood flow to the uninvolved psoriatic skin of psoriatics and that to the skin of healthy controls.