Clinical trial NCT05858723: Repeated Open Application Test (ROAT) Study With Hydroperoxides of Linalool
Official title: Allergic Contact Dermatitis to Hydroperoxides of Linalool - a Repeated Open Application Test (ROAT) Study
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: NA
Conditions: Allergic Contact Dermatitis
Lead sponsor: National Allergy Research Center, Denmark
Sponsor class: OTHER
First posted: 2023-05-15
Enrollment: 40
Sex: ALL
Minimum age (years): 18
Maximum age (years): 110
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

Brief summary: 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


Eligibility criteria: 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.

Primary outcomes:
measure: Establish the optimal patch test concentration to diagnose allergic contact dermatitis to hydroperoxides of linalool via a Repeated Open Application Test
timeFrame: 6 months
measure: 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
timeFrame: 6 months
Secondary outcomes:
measure: The Lin-OOH chemicals can penetrate the skin barrier and reside in the local skin tissue
timeFrame: 12 months
Other outcomes:
Locations:
Study officials:
References: