The laser Doppler flowmeter, an instrument highly sensitive to changes in blood flow velocity in the dermal microvascular bed, was used to examine a sympathetic vasomotor response (SVR) in 40 patients with lateral epicondylitis. There was a significant association between the absence of a normal SVR in the skin overlying the affected enthesis compared with the unaffected contralateral epicondyle (P < 0.01). These results suggest that local dysfunction of the sympathetic nervous system may be associated with the pathogenesis of anatomically discrete pain in the enthesopathy of epicondylitis.

SummaryThe laser Doppler flowmeter (LDF), which measures changes in cutaneous blood flow, and the transcutaneous oxygen electrode which measures cutaneous perfusion, were used to study reflex changes in the microcirculation of the shoulder in 38 patients with frozen shoulder and 10 normal controls. In all controls and 22 patients with frozen shoulder, a normal LDF response to inspiration/expiration was observed. In 16 patients with frozen shoulder, LDF responses were either unilaterally or bilaterally absent. Comparison between the two patient groups showed a significant association (x z = 6.43, P< 0.02) between abnormality of response and the persistence of pain. TcPo z was in the normal range in all patients and controls. These findings suggest that the LDF together with the TcPo z may be a useful method of studying the skin microcirculation over the shoulder. IntroductionFrozen shoulder is a common clinical condition of unknown aetiology although clinical, radiological and thermographic studies have suggested an association between the disorder and chronic cervical spine disease". An explanation which has been proposed for this association is that frozen shoulder results from a local abnormality of autonomic dysfunction.Most currently available methods for assessing autonomic dysfunction, such as measurement of the variation of the RR interval or heart rate response to standing, indicate generalized rather than localized abnormalities-, Laser Doppler flowmetry (LDF), a technique which measures changes in cutaneous blood flow, and transcutaneous oxygen tension measurement (TcPo z) which measures cutaneous oxygen tension, have recently been used to study reflex changes in the skin microcirculation in hands and feet of patients with spinal cord transections", These cutaneous vasomotor reflexes were originally described by

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Summary In this double‐blind study we have investigated the vascular effects of prostaglandin, (PG) D2, in normal skin and compared these effects with histamine and the initial PGD2 metabolite 9α, 11β‐PGF2. In eight healthy subjects the vascular response to intradermal injections of histamine, PGD2, a combination of histamine and PGD2, and 9α, 11β‐PGF2, was assessed by measurement of the weal and flare area. Histamine caused dose‐related increases in weal area (P<0.01). The weal response due to PGD2 was greater than saline control only at a dose of 71.0 and 710 nmol (P<0.05). Because of the small size of the weal produced by PGD2 when compared with histamine, it was not possible to determine their relative potencies. Histamine and PGD2 caused dose‐related increases in flare area (P<0.05), and when compared at a response level of 10 cm2 and 15 cm2, histamine was 45 and 251 (P<0.01) times more potent than PGD2 in molar terms. Weal and flare responses due to 9α, 11β‐PGF2 were similar to those observed with the equimolar concentration of PGD2. The weal and flare responses when PGD2 and histamine when combined were not significantly different from that predicted by a purely additive effect. We conclude that histamine is likely to be an important mediator contributing towards increased vascular permeability and vasodilatation following immunological activation of skin mast cells in vivo, while PGD2 and its metabolite 9α, 11β‐PGF2 play only a minor role.

Summary The use of laser Doppler flowmetry (LDF) in determining changes in cutaneous blood flow following intradermal injection of histamine has been investigated in this double‐blind study. In eight subjects blood flow (LDF) and weal‐and‐flare area (planimetry) were measured at regular intervals for 1 hr following 50‐μl injections of different concentrations of histamine (6.5 ± 10−5 ‐6.5 ± 10−3 M) and saline. The mean maximum increase in LDF values over the flare was at least nine‐fold greater than the baseline values for all three concentrations of histamine injected. When the LDF values observed at different sites were integrated to obtain the ‘LDF response’ it was possible to demonstrate concentration‐related increases in blood flow and to differentiate clearly between the different concentrations of histamine and saline for up to 30 min after injection. During this period, the repeatability and the time course of the LDF response was comparable with that of the flare area. These studies suggest that the non‐invasive technique of LDF is a sensitive and reproducible method for quantifying the changes in cutaneous blood flow that occurs for the first 30 min after intradermal injection of histamine.