Specific features of psoriasis vulgaris under the ultraviolet dermoscopy

•Ultraviolet-dermoscopy is a rapid non-invasive and convenient tool for psoriasis diagnosis.•Red fluorescence which is only observed in psoriatic plaques under ultraviolet-dermoscopy could help differential diagnosis of erythrosquamous dermatoses.•Glomerular vessels, Auspitz sign and red fluorescence, simultaneously observed via ultraviolet-dermoscopy, indicated the severity of psoriasis.