Seasonal differences in finger skin temperature and microvascular blood flow in healthy men and women are exaggerated in women with primary Raynaud's phenomenon

Abstract

Aims Patients with primary Raynaud's phenomenon (PRP) have more severe symptoms in the winter. The aetiology of this is more complex than simply increased vasoconstriction in response to the immediate ambient temperature. The aim of this study was to investigate differences in skin temperature (Tsk), microvascular blood ow and responses to endothelium-dependent and independent vasodilators in healthy controls, and women with PRP under identical environmental temperatures but in different seasons. Methods Ten women with PRP were compared with age matched women (10) and men (10). Finger skin responses were recorded immediately on arrival, after stabilizing in a temperature regulated laboratory at 22±24u C, and at matched warm (35u C) and cold (15u C) Tsk in the winter and summer. Baseline red blood cell¯ux (r.b.c.¯ux), and the change in¯ux in response to iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP) were recorded by laser Doppler¯uxmetry at the warm and cold Tsk. Results Arrival Tsk were signi®cantly cooler for all subjects during the winter (mean seasonal difference x2.6u C, P<0.0001), and markedly colder in subjects with PRP (mean seasonal difference x3.5u C, P<0.0005). Statistically signi®cant seasonal differences persisted in all subjects at stable Tsk despite an identical laboratory temperature (mean difference 1.3u C, P<0.0001). To achieve comparable controlled ®nger Tsk a signi®cantly colder local environment was required for male controls (mean of x2.1u C, P<0.0001), and a signi®cantly warmer environment for subjects with PRP (mean of + 2.4u C, P<0.0001) compared with female controls. This needed to be warmer in the winter, by a mean of 2.4u C, than the summer for all subjects. Vasodilatation in response to ACh, but not SNP, was signi®cantly smaller (P<0.0001) in the PRP group compared with the female controls for all visits, with most of this difference arising in the winter visits (P<0.01). Conclusions There is a seasonal and persistent in¯uence on ®nger Tsk, and microvascular blood¯ow in healthy men and women, which modi®es the observed responses to immediate changes in ®nger Tsk. The seasonal differences are greater in women than men, and are further exaggerated in women with PRP, in whom this is associated with reduced endothelium-dependent vasodilatation.

MQX‐503, a novel formulation of nitroglycerin, improves the severity of Raynaud's phenomenon: A randomized, controlled trial

“…The second limitation of our study is the influence of ambient temperature on the severity of RP (29,30). Ambient temperature variability during the study period affects all trials of therapy for RP.…”

Chronobiology: Biological Clocks and Rhythms of the Skin

“…In general, skin temperature and red blood cell fl ux assessed after acclimatization were consistently lower in winter than in summer. Seasonal variations were more pronounced in women than in men [35] . Men had the warmest fi ngers on arrival, and women needed less cooling to achieve the same skin temperature as men at 15 ° C. Various seasonal effects were observed in a timecourse study performed on 22 presumably Japanese subjects, using the neck of 11 males and the ventral forearm of 11 females as the test areas [36] .…”

“…In a small scale study, seasonal differences in fi nger skin temperature were assessed [35] . Skin temperature was assessed after arrival, after acclimatization and after decreasing (15 ° C) or increasing (35 ° C) the ambient temperature.…”

Seasonal Variation in Critical Limb Ischemia Requiring Endovascular Therapy: An Analysis of a Multicenter Database of Japanese Patients with Critical Limb Ischemia Undergoing Endovascular Therapy

“…Cold stimuli would cause vasoconstriction and deteriorate limb ischemia. Indeed, a few previous studies reported that a cold environment more severely impairs the peripheral microvascular blood flow 14,15) . However, there remain questions regarding the influence of cold temperatures on the peripheral macrovascular blood flow 16) .…”