Objective measurement of erythema in psoriasis using digital color photography with color calibration

Abstract

Background Traditional metrics for evaluating the severity of psoriasis are subjective, which complicates efforts to measure effective treatments in clinical trials. Methods We collected images of psoriasis plaques and calibrated the coloration of the images according to an included color card. Features were extracted from the images and used to train a linear discriminant analysis classifier with cross-validation to automatically classify the degree of erythema. The results were tested against numerical scores obtained by a panel of dermatologists using a standard rating system. Results Quantitative measures of erythema based on the digital color images showed good agreement with subjective assessment of erythema severity (κ = 0.4203). The color calibration process improved the agreement from κ = 0.2364 to κ = 0.4203. Conclusions We propose a method for the objective measurement of the psoriasis severity parameter of erythema and show that the calibration process improved the results.

Development and clinical validation of a novel photography‐based skin pigmentation evaluation system: a comparison with the calculated consensus of dermatologists

“…In our study, five dermatologists participated in this process of making a clinical judgment, and the majority was three. This number is considered sufficient based on recent studies . If less than five dermatologists participate, CCAP will not have enough reliability.…”

Hyperspectral Imaging and Classification for Grading Skin Erythema

“…Skin Erythema, also called cutaneous inflammation, is a symptom associated with diverse cutaneous diseases [1] such as psoriasis [2,3] and acne lesions [4], as well as with skin injuries such as pressure sores and burns [5,6]. In more extreme cases of thrombocytopenia, cutaneous inflammation is claimed to be a trigger for a life-threatening hemorrhaging condition [7].…”

“…Ideally, techniques to evaluate erythema should be quantitative in nature, contact-free and minimally invasive [6]. Various imaging technologies have been investigated for this purpose, including colorimetry [12,13], diffuse reflectance spectroscopy (DRS) [11], laser Doppler flowmeter [8], digital photography [3,4], confocal microscopy [1], optical coherence tomography [1], ultrasound [10], and magnetic resonance imaging [14]. In spite of the various techniques under investigation, erythema assessment by VA with the naked eye is still considered the gold standard [15].…”

Development and clinical validation of a novel photography‐based skin erythema evaluation system: a comparison with the calculated consensus of dermatologists

“…These modalities need to be validated objectively for dermatologists, patients and regulatory agencies . Various studies are in progress on both improvement of skin conditions and their objective measurement . The evaluation of skin condition is highly dependent on dermatologists’ judgements based on naked eyes, and the results can vary depending on the dermatologists’ expertise and bias .…”