This study aims to investigate how the physical placement of hand sanitizer in consultation rooms affects patient trust and feelings of disease stigma. While hand hygiene is an essential infection control measure in healthcare, performing it immediately in front of patients with visible, non-communicable conditions (such as psoriasis) might inadvertently make patients feel rejected or stigmatized.This study uses a randomized controlled design to evaluate if a simple environmental modification-changing the spatial location of the hand sanitizer-can naturally nudge physicians to alter their hand hygiene timing without compromising safety. Researchers will discreetly observe the hand hygiene behavior of outpatient dermatologists and ask participating psoriasis patients to complete a brief, anonymous questionnaire regarding their trust in the physician, feelings of stigma, and overall satisfaction with the consultation. The goal is to provide evidence for patient-centered hospital space designs that protect patient psychological well-being while maintaining hygiene standards.

Background and Rationale:

Patients with visible non-communicable diseases, such as psoriasis, often experience high levels of disease-related stigma and are highly sensitive to physician behaviors. Although hand hygiene is a cornerstone of infection control, executing it in certain clinical scenarios may be misinterpreted by patients as the physician's "fear" or "disgust" toward their condition. This misinterpretation can exacerbate their psychological burden and impair the doctor-patient relationship. Environmental engineering theories suggest that micro-modifications to physical hospital spaces can significantly alter medical behavior patterns (such as sitting versus standing during consultations) without relying on resource-intensive training or administrative supervision.Study Design and Methodology:

This is a single-center, double-blind, randomized controlled deception trial conducted in an outpatient dermatology setting. The core intervention involves manipulating the spatial location of the hand sanitizer in the consultation room through randomized assignment to determine its causal effect on physician behavior and subsequent patient psychological outcomes. To minimize the Hawthorne effect and behavioral bias, a double-blind deception mechanism is employed. Physicians are informed that the study is simply for medical students to observe general consultation workflows, while patients are told they are participating in a routine outpatient service satisfaction survey. The true nature of the environmental intervention and its behavioral focus is concealed until a debriefing session at the conclusion of the study.Observations and Assessments:

During the study, trained observers will discreetly record the physicians' hand hygiene patterns in the consultation room. After the consultation concludes, participating psoriasis patients will be guided to an independent area to complete an anonymous electronic questionnaire (taking approximately 10 minutes).The primary psychological outcomes assessed include:Doctor-patient trust, measured by the 11-item Trust in Physician Scale (TPS).Intensity of disease stigma, measured by the 27-item Chinese version of the Feelings of Stigma Questionnaire (FSQ).Secondary outcomes include overall patient satisfaction evaluated across five dimensions, and the documentation of physician hand hygiene timing patterns under different environmental layouts.Statistical Analysis:

Analyses will utilize a prospectively defined dataset framework. Multivariate linear regression will be used to analyze the psychological impact pathways on trust and stigma, adjusting for demographic variables. Generalized estimating equations (GEE) and mixed linear models will be applied for sensitivity analyses to account for the correlation of multiple observations from the same physician.

Inclusion Criteria:

For Patients:

• Aged 18 years or older.
• Diagnosed with psoriasis and receiving treatment at the designated psoriasis specialty outpatient clinic during the study period.
• Legally capable of signing the informed consent form and cognitively able to understand and complete the questionnaire (independently or with assistance from family members).

For Physicians:

• Hold a registered practicing qualification in the Dermatology Department of Huashan Hospital Pudong Branch and are qualified for independent outpatient consultations.
• Scheduled to continuously undertake outpatient work in the designated consultation rooms during the study period.
• Voluntarily sign the informed consent form for behavioral observation.

Exclusion Criteria:

For Patients:

• Severe visual, hearing, or speech impairments leading to basic doctor-patient communication barriers.
• Diagnosed with psychiatric disorders (e.g., schizophrenia, severe depression) that, as assessed by a specialist, may interfere with the authenticity of the questionnaire responses.
• Presenting with a clinical state requiring emergency treatment during the visit, such as acute infection of skin lesions or generalized pustules.

For Physicians:

• Non-permanent practicing staff of the hospital, such as visiting physicians or rotating medical students.
• Unable to independently perform hand hygiene procedures due to physical/limb dysfunction.