Abstract
Introduction: Trichoscopy greatly facilitates clinical diagnosis in patients with hair loss and may decrease the necessity for histopathological examination. Structures which may be revealed by trichoscopy include hair shafts, hair follicle openings, the perifollicular epidermis, and cutaneous microvessels. Cutaneous microvessels revealed in trichoscopy may vary in type and number depending on the scalp area, type of the disease, and its activity. Firm direct pressure (diascopy) might result in their blanching, but as of yet, there are no studies on the types of vessels that do or do not blanch on applying pressure. Methods: We studied interfollicular twisted loops in 16 cases of biopsy-confirmed scalp psoriasis and 37 cases of arborizing vessels in normal subjects and seborrheic dermatitis patients. Results: We observed that all arborizing red line vessels blanched on applying pressure. Instead, the vast majority of twisted and simple loops, despite their vascular nature, did not blanch on performing diascopy. Conclusion: In the light of these findings, diascopy of vascular changes in hair loss patients might provide additional clues for a proper diagnosis, especially in differentiating scalp psoriasis, seborrheic dermatitis, and discoid lupus erythematosus.
