Objective assessment of psoriasis erythema for PASI scoring

Abstract

Skin colour is vital information in dermatological diagnosis. It reflects pathological condition beneath the skin and commonly being used to indicate the extent of a disease. Psoriasis is a skin disease which is indicated by the appearance of red plaques. Although there is no cure for psoriasis, there are many treatment modalities to help control the disease. To evaluate treatment efficacy, PASI (Psoriasis Area and Severity Index) which is the current gold standard method is used to determine severity of psoriasis lesion. Erythema (redness) is one parameter in PASI. Commonly, the erythema is assessed visually, thus leading to subjective and inconsistent result. In this work, we proposed an objective assessment of psoriasis erythema for PASI scoring. The colour of psoriasis lesion is analyzed by DeltaL, Deltahue, and Deltachroma of CIELAB colour space. References of lesion with different scores are obtained from the selected lesions by two dermatologists. Results based on 38 lesions from 22 patients with various level of skin pigmentation show that PASI erythema score can be determined objectively and consistent with dermatology scoring.

A comparison study of clinician-rated atopic dermatitis outcome measures for intermediate- to dark-skinned patients

“…The clinician's perception of inflammation in patients with SOC may be underestimated due to the relative absence of erythema and possible grey‐coloured hue in patients with SOC. In this case, active AD may be mistaken for other pathologies such as postinflammatory hyperpigmentation . Finally, clinical experience of managing patients with SOC can vary considerably between clinicians, increasing the variability in assessment of AD in patients with SOC.…”

Improvement effects of a novel Chinese herbal formula in imiquimod and IL-23-stimulated mouse models of psoriasis

“…The severity of psoriatic lesions on the dorsal area of mice was assessed by psoriasis area and severity index (PASI). The researcher scored the degree of erythema and skin scaling on a scale of zero to four, where 0: no symptoms, 1: slight, 2: moderate, 3: severe, and 4: very severe [ 17 ]. The dorsal skin thickness was measured using an electronic vernier caliper which was placed on the middle line of the dorsal area.…”