Repeated Open Application Test (ROAT) Study With Hydroperoxides of Linalool

Allergic Contact Dermatitis to Hydroperoxides of Linalool - a Repeated Open Application Test (ROAT) Study

Linalool is currently one of the most used fragrance substances in cosmetic and household products. Previous studies report a high prevalence (5.9-11.7%) of contact allergy to hydroperoxides of linalool (Lin-OOH)1.0% in pet. among patch tested patients. The optimal test concentration of Lin-OOH in patch tests is not known and requires further investigation. It is of great importance to establish the optimal test concentration and elicitation threshold of Lin-OOH to improve diagnosis and prevent development of Allergic Contact Dermatitis (ACD).

We want to mimic real-life exposure to Lin-OOH, by conducting a ROAT (Repeated Open Application Test) study, on 40 adult participants (20 patients with confirmed contact allergy to Lin-OOH, and 20 healthy participants) to low doses of Lin-OOH using a simulated "perfume", during a maximum of 21 days of exposure.

With this knowledge, we aim to:

1. Establish the optimal patch test concentration to diagnose ACD to Lin-OOH
2. In case of confirmed contact allergy, examine the threshold value for the development of ACD upon daily exposure to a simulated leave-on cosmetic product

Study Overview

• Status: Not yet recruiting
• Conditions: Allergic Contact Dermatitis
• Intervention / Treatment: Diagnostic test: ROAT

• Study Type: Interventional
• Enrollment (Anticipated): 40
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Allergic participants:

1. Inclusion criteria

   • Positive (at least one reading) or doubtful patch test (at least two readings) result to hydroperoxides of Linalool within the last ten years
   • Aged 18 years or older
   • Received written and verbal information of the study
   • Signed written consent form

2. Exclusion criteria

   • Active eczema in test areas (volar forearms)
   • Pregnancy or breast feeding
   • Treatment with topical corticosteroids or other immune suppressants on/near test areas within two weeks prior to study start
   • Systemic immune-suppressant treatment within seven days prior to study start
   • UV exposure of test areas within three weeks prior to study start
   • Unable to cooperate or communicate with the investigators

Healthy controls:

1. Inclusion criteria

   • Aged 18 years or older
   • Received written and verbal information of the study
   • Signed written consent form

2. Exclusion criteria

   • Known or possible contact allergy to hydroperoxides of Linalool
   • Known contact allergy to other fragrance allergens
   • Active eczema or other known relevant skin diseases
   • Pregnancy or breast feeding
   • Treatment with topical corticosteroids or other immune suppressants on/near test areas within four weeks prior to study start.
   • Systemic immune-suppressant treatment within four weeks prior to study start.
   • UV exposure of test areas within three weeks prior to study start.
   • Participation in other clinical studies within four weeks prior to study start.
   • Unable to cooperate or communicate with the investigators.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Healthy participants	Diagnostic test: ROAT; Repeated Open Application Test; Other Names: Patch testing and punch biopsies
Experimental: Allergic participants	Diagnostic test: ROAT; Repeated Open Application Test; Other Names: Patch testing and punch biopsies

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Establish the optimal patch test concentration to diagnose allergic contact dermatitis to hydroperoxides of linalool via a Repeated Open Application Test	Establish the optimal patch test concentration to diagnose allergic contact dermatitis to hydroperoxides of linalool via Repeated Open Application Test	6 months
In case of confirmed contact allergy, examine the threshold value for the development of ACD upon daily exposure to a simulated leave-on cosmetic product	In case of confirmed contact allergy, examine the threshold value for the development of ACD upon daily exposure to a simulated leave-on cosmetic product	6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The Lin-OOH chemicals can penetrate the skin barrier and reside in the local skin tissue	Chemical analysis of skin punch biopsies from the exposed skin of the patients' lower back: time of flight secondary ion mass spectrometry (ToF-SIMS) analysis of Lin-OOH in the skin.	12 months

Collaborators and Investigators

• Sponsor: National Allergy Research Center, Denmark

Study record dates

Study Major Dates

• Study Start (Anticipated): August 1, 2023
• Primary Completion (Anticipated): January 1, 2024
• Study Completion (Anticipated): July 1, 2024

Study Registration Dates

• First Submitted: May 2, 2023
• First Submitted That Met QC Criteria: May 12, 2023
• First Posted (Actual): May 15, 2023

Study Record Updates

• Last Update Posted (Actual): May 15, 2023
• Last Update Submitted That Met QC Criteria: May 12, 2023
• Last Verified: May 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Skin Diseases; Immune System Diseases; Hypersensitivity; Skin Diseases, Eczematous; Hypersensitivity, Delayed; Dermatitis; Dermatitis, Contact; Dermatitis, Allergic Contact
• Other Study ID Numbers: H-23018400

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No