Endothelial and axon reflex vasodilatation to acetylcholine in rosacea-affected skin

Abstract

Rosacea is a chronic skin disorder, characterized by persistent painful facial flushing and often accompanied by papules and pustules. To investigate the mechanism of facial flushing in rosacea, acetylcholine was administered by iontophoresis to a 10-mm diameter site in the forehead of 31 patients with rosacea and in 29 controls of similar age and sex distribution. During the iontophoresis, current strengths doubled in eight steps from 2.5 to 320 μA. For each step, skin blood flow was monitored during 60 s of iontophoresis and for 2 min afterwards with laser Doppler flow probes at the site of iontophoresis and 5-8 mm away in the region of axon reflex vasodilatation. Vascular responses to acetylcholine were similar in patients and controls, but stinging sensations were greater in patients than in controls at the most intense current strength. In addition, axon reflex vasodilatation was greater in patients with severe than mild rosacea. These findings suggest that activation of nociceptive nerve fibres contributes to skin sensitivity in patients with rosacea, and that axon reflexes augment flushing in patients with the most severe symptoms.

Noninvasive objective skin measurement methods for rosacea assessment: a systematic review

“…67,82 For laser Doppler, absolute values are meaningless without measuring sympathetic flux changes and blood vessel density, which is impossible with noninvasive techniques. 89,118 Control for these factors was often not described or accounted for in the reviewed articles, and comparisons with normal skin were scarce. Additionally, biophysical tools are probe-related; they only cover a small facial area, questioning representativeness of the entire face.…”

Integrative concepts of rosacea pathophysiology, clinical presentation and new therapeutics

“…Skin hypersensitivity and flushing augmentation have been directly linked to neural stimulation in rosacea . Sensory neuron density is moderately increased in the erythematotelangiectatic (ETR) subtype of rosacea, and increased density of TRP ion channels on sensory neurons, blood vessels and immune cells has also been reported across all cutaneous rosacea subtypes …”

“…Skin hypersensitivity and flushing augmentation have been directly linked to neural stimulation in rosacea. 36 open question with significant therapeutic implications ( Fig. 3).…”

Pathogenesis and clinical presentation of rosacea as a key for a symptom‐oriented therapy

“…The psychosocial strain of rosacea is comparable to other conditions such as work‐related contact dermatitis or vitiligo . Rosacea patients have a higher incidence of shame , depressions , and social phobias , as a result of which they increasingly avoid social contact. Reduced quality of life was found in several studies and confirmed in a meta‐analysis .…”