Biophysical and ultrasonographic changes in pityriasis rosea compared with uninvolved skin.

Background: Pityriasis rosea (PR) is a common, self-limited, inflammatory papulosquamous skin disease with a possible viral etiology.
Objective: The goal of this study was to evaluate skin biophysical properties in patients with PR compared with uninvolved skin to better understand the pathogenesis of PR.
Methods: Stratum corneum hydration, transepidermal water loss, surface friction, pH, sebum, melanin, erythema, temperature, elasticity parameters (R0, R2, R5), thickness, and echodensity of the epidermis and dermis were measured on lesions of classic PR in 21 patients and compared with control sites (average of uninvolved perilesional and symmetrical skin) with a paired t test.
Results: Stratum corneum hydration ( p  < .001), R0 ( p  = .003), R2 ( p  = .001), R5 ( p  = .003), and echodensity of the dermis ( p  = .006) were significantly lower, whereas transepidermal water loss ( p  = .001), pH ( p  < .001), and erythema ( p  < .001) were significantly higher in PR lesions. There was no significant difference in friction index, sebum, melanin content, temperature, thickness of the epidermis and dermis, and echodensity of the epidermis between PR and normal skin.
Conclusion: PR skin is characterized by certain alterations in biophysical properties, which are mostly correlated with histologic changes. These changes may be helpful in early, noninvasive diagnosis of PR.
(© 2020 Published by Elsevier Inc. on behalf of Women's Dermatologic Society.)