Measuring Psoriasis Severity at Home

Summary

This paper details the creation of a Psoriasis Thickness Reference Card, enabling psoriasis patients to self-assess their psoriasis plaque thickness without the need for physician assistance. Additionally, the precision of self-assessment for psoriasis redness and scaliness by employing reference images depicting various skin tones is assessed.

Abstract

Psoriasis plaque severity metrics, such as induration (thickness), erythema (redness), and desquamation (scaliness), are associated with the subsequent development of psoriatic arthritis (PsA) among cutaneous-only psoriasis patients (patients with skin or nail psoriasis but no psoriatic arthritis). These metrics can be used for PsA screening. However, a key challenge in PsA screening is to optimize accessibility and minimize costs for patients, while also reducing the burden on healthcare systems. Therefore, an ideal screening tool consists of questions that patients can answer without a physician's assistance. Although reference images can be used to help a patient self-assess erythema and desquamation severity, a patient would need a tactile induration reference card to self-assess induration severity. This protocol describes how to create an induration reference card, the Psoriasis Thickness Reference Card, as well as how to use it to assess lesion induration severity. Administration of reference images for erythema and desquamation and a Psoriasis Thickness Reference Card for induration to 27 psoriasis patients showed that patients were moderately successful at self-assessing the severity of these three metrics. These findings support the feasibility of a future PsA screening test that patients can complete without the need for physician assistance.

Introduction

Psoriatic arthritis (PsA) is an inflammatory arthritis that develops in approximately 2.9% of patients with psoriasis each year^1,2. Early prediction of which patients will develop PsA is crucial for a patient's quality of life as a diagnostic delay of as little as six months may cause irreversible damage to the joints³. A previous study had identified features associated with early-stage PsA. The three components of the Investigator's Global Assessment (IGA)-induration (thickness), erythema (redness), and desquamation (scaliness)-were highly correlated with each other and were n....

Protocol

This study was approved by the University of Utah Institutional Review Board (IRB_00137694). Twenty-seven psoriasis patients at the University of Utah dermatology clinic were enlisted to complete a questionnaire about psoriasis severity at the time of the questionnaire's administration. All patients provided informed consent and completed the questionnaire without instructions from research or medical personnel, either before or immediately after the dermatologist's assessment.

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Discussion

Protocol step 1.4 is a crucial aspect of the proper construction of the Psoriasis Thickness Reference Card. To achieve an accurate representation of plaque thickness, it is imperative to avoid placing the tape vertically or flush against the vertical edge of the stack of sticky notes. If the tape is positioned in such a manner, the sharp edge of each stack will not mimic the feel of a psoriasis plaque. The tape should be applied in a way that creates a smooth slope connecting the stack to the paper.

Materials

Name	Company	Catalog Number	Comments
Post-it Notes, 1 3/8 in x 1 7/8 in, Canary Yellow, 6 Pads/Pack	3M	00021200569029	The smallest sized sticky notes (5.08 cm height x 5.08 cm width or 5.08 cm height x 3.81 cm width) work best with the printed template. The thickness of each sticky note should be between 0.09 and 0.1 mm; sticky notes from the brands Post-it, Pen+Gear, and Office Works meet these requirements.
Printworks Printer and Copy Paper - 500 Pack - White	Paris Corporation	0009014600006	Any brand of printer paper is acceptable; if recreating the template manually rather than printing, any brand of paper is acceptable.
R	http://www.r-project.org		The R programming language version 4.3.1 was used to analyze the data in this study.
Scotch Magic Tape Dispensered Rolls	3M	00021200000041	Any brand of smooth adhesive tape is acceptable; do not use tape with a coarse texture.