Allergic Contact DermatitisPhase 4NCT07765563
Reliability of Expired Allergens in Patch Testing: A Comparative Study With Non-Expired Series
A Phase 4 study testing Patch 1 (Expired) and Patch 2 (non-expired) in people with Allergic Contact Dermatitis, run by University of Calgary at 1 site in Canada.
Trial summary
Patch testing remains the gold standard in the diagnosis of allergic contact dermatitis. Patches used in testing consist of a wide spectrum of allergens, with variability in the stability of products over time. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Allergic Contact Dermatitis
- What is being tested?
- Patch 1 (Expired) and Patch 2 (non-expired)
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 100 participants
- Where
- 1 siteCanada
- Study dates
- Sep 2026to Dec 2027
- Phase
- Phase 4
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adults (age 18 years or older) referred for patch testing.
Who cannot join
- Relative or absolute contraindication to patch testing
- Wide spread dermatitis prior to patch placement
- Inability to return to clinic for reading of results
- Patient non-consenting
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Canada1 site
Richmond Road Diagnostic Treatment Centre
Calgary, Alberta, T2T 5C7
Dylan Hollman, Medical Doctor, 1-403-955-8444, dylan.hollman@ucalgary.ca
Laurie Parsons, Medical Doctor
About this study
Patch testing remains the gold standard in the diagnosis of allergic contact dermatitis. Patches used in testing consist of a wide spectrum of allergens, with variability in the stability of products over time. Due to limited allergen stability, careful storage and preparation is needed to prevent product degradation over time. Expiration dates are provided by manufacturers to ensure stability and reactivity, while minimizing the risk of product degradation contributing to inaccurate testing results. Preparation of patch series can be time intensive and procurement of allergens comes with an associated economic burden. Expired allergens are not routinely used in patch testing, however many clinics have expired allergens accessible. There is paucity of evidence comparing the reactivity of expired vs non-expired patch series. If expired allergens remain effective, this could result in significant cost-savings and accessibility implications for dermatology practice.
Read the detailed description
In brief, review of the medical literature showed two comparable studies out of India and Spain suggesting that expired allergen series may be used beyond their labeled expiry dates, with some variability noted amongst duration of expiry, that the investigators will also aim to analyze.
Regarding allergen stability, there were also several studies focused on this domain. The European Society of Contact Dermatitis (ESCD) released guidelines in 2015, outlining optimal methods for allergen storage such as storage at 4 degrees celsius and strict protection from ultraviolet light exposure. While most allergens are dispersed in petrolatum (white soft paraffin), some substances are better tested in solutions such as water (aqueous) or ethanol. Several allergens with high vapour pressure require more frequent renewal and strict storage conditions such as fragrance chemicals, acrylates and isocyanates. Other substances such as glutaraldehyde in petrolatum (pet.) and formaldehyde in aqueous solution (aq.) are susceptible to instability and deterioration. An additional study assessed volatility over time of several select compounds and described high volatility in acrylates, glutaraldehyde, and fragrances, while describing partial volatility of formaldehyde and low volatility of nickel sulfate.
Study participants will include all eligible adults seen in patch testing clinic who maintain an indication for patch testing and consent to participation. The study will be utilizing 10 allergens from the North American Contact Dermatitis Group (NACDG) 80 Series for inclusion in the study.
The allergen selections are primarily based on compounds with a higher likelihood for volatility, in addition to inclusion of two comparator compounds with lower volatility. Expiration intervals include 1 year, 2 years, 3 years, and 4 years. The compounds selected are as follows, including their dispersion compound: nickel sulfate hexahydrate (5% pet.), cobalt (II) chloride hexahydrate (2.5% pet.), hydroperoxides of linalool (1% pet.), hydroperoxides of limonene (0.3% pet.), fragrance mix 1 (8.0% pet.), myroxylon pereirae resin (balsam of Peru) (25.0% pet.), methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) (0.02% aq.), formaldehyde (2.0% aq.), tixocortol-21-pivalate (1.0% pet.), and budesonide (0.1% pet.).
The patch testing results will be compared to corresponding non-expired allergens from the same manufacturer with the same preparation tested simultaneously. Both series will be placed simultaneously in differing locations on the participant's back, ensuring both are placed in sun protected areas with no underlying dermatitis.
Once in clinic, standard patch test series are applied on patch testing day, with the participant instructed not to shower or scratch the area throughout testing. At 48h, the patches are removed and photos are taken of the participant's back which are sent to the Dermatologist for virtual reading. At either 96h or 120h, the participant returns to the clinic for final reading. Both morphology and intensity of positives are graded on a standard patch test scale (irritant reaction), +/- for doubtful, + for erythema and infiltration, ++ for edematous or vesicular and +++ for spreading, bullous or ulcerative. Positive allergens scored + or greater are considered a true allergic contact allergen and assessed for relevance based on clinical context. The Dermatologist provides information sheets on all positive allergens, counsels on the relevance to their clinical history and allergen avoidance going forward, as well as providing the participant with a safe product list via the ACDS Contact Allergen Management Program (CAMP) database.
The investigators are aiming for enrolment of 100 participants which should theoretically provide the study with at least 5-10 participants testing positive to each of the four listed allergens with higher volatility and 20+ participants testing positive to the allergens with lower volatility. The investigators are aiming to assess concordance between expired and non-expired allergen reactions (positive vs negative), in addition to agreement in reaction intensity, differences in morphology, rates of false positives/negatives compared to control and concordance of irritant reaction between interventions.
The study will serve to lend valuable evidence as to whether expired allergens maintain clinical utility and could serve to reduce product waste, lower the economic burden and further improve accessibility of patch testing for use in resource limited settings.
- Conditions
- Allergic Contact Dermatitis
- Being tested
- Patch 1 (Expired), Patch 2 (non-expired)
- Keywords
- contact dermatitis, patch testing
- Medical subject headings
- Dermatitis, Allergic Contact, Dermatitis, Contact
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Patch 1 (Expired)Biological
All enrolled participants will be simultaneously patch tested with both expired and non-expired patches. Therefore, there is no difference in intervention amongst study participants.
Patch 2 (non-expired)Biological
All enrolled participants will be simultaneously patch tested with both expired and non-expired patches. Therefore, there is no difference in intervention amongst study participants.
| Study group | Role | What they receive |
|---|---|---|
| Enrolled Study Participants | Other | All enrolled participants will be simultaneously patch tested with both expired and non-expired patches. Therefore, there is no difference in intervention amongst study participants. Receives: Biological: Patch 1 (Expired); Biological: Patch 2 (non-expired) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Patch Testing Response (Positive/Negative) Concordance Rate (%) Between Non-Expired and Expired Allergens
Each allergen will be graded on response using a standard patch test scale including: irritant reaction ['IR'], '+/-' for doubtful, '+' for erythema and infiltration, '++' for edematous or vesicular and '+++' for spreading, bullous or ulcerative response that will be graded by the participating Dermatologist. Reactions graded '+', "++", or "+++" are consider a positive result. Concordance rate will be expressed as a percentage (%) between tested allergens that were non-expired and that were expired (i.e. Nickel sulfate hexahydrate was found to have a 92% concordance rate, meaning that in 92% of cases, the Nickel allergen in the non-expired and expired patches were both found to both be either positive or negative while in 8% of cases the response differed per the scale listed above.)
Measured: Standard patch test series are applied on Day 0. Participant removal of patches on Day 2 and self photos taken and sent to Dermatologist for virtual reading. Final reading completed in clinic by Dermatologist on Day 4 or 5, recording reaction scores.
Secondary outcomes (3)
Reaction/Morphology Scoring Concordance (%)
For each positive allergen, severity (i.e. '+/-', '+', '++', "+++") and morphology (i.e. erythema, infiltration, edematous, vesicular, bullous, ulcerated) will be recorded. Concordance rate will be expressed as a percentage (%) between tested allergens that were non-expired and that were expired (i.e. Nickel sulfate hexahydrate was found to have a 92% concordance rate, meaning that in 70% of cases, the Nickel allergen in the non-expired and expired patches were both found to have the exact same severity and morphology, while in 30% of cases the severity and/or morphology differed per the scale listed above.)
Measured: Standard patch test series are applied on Day 0. Participant remove patches on Day 2, photos taken and sent to Dermatologist for virtual reading. Final reading completed in clinic by Dermatologist on Day 4 or 5, recording reaction scores, morphology.
Stability Concordance (%) Amongst Mediums
Each allergen is suspended within a medium, either petrolatum or aqueous solution. Not only will concordance (%) of positive and negative reactions be assessed amongst allergens and compared between non-expired and expired, but also between mediums to determine if there is a difference in stability over time amongst mediums used to determine if particular mediums result in degradation over time.
Measured: Standard patch test series are applied on Day 0. Participant remove patches on Day 2, photos taken and sent to Dermatologist for virtual reading. Final reading completed in clinic by Dermatologist on Day 4 or 5, recording reaction scores, morphology.
Irritant Reaction Rates (%)
Final patch reading will score reactions on a standarized scale, with irritant reaction representing a negative reaction. However, we will compare rates and concordance (%) of irritant reactions between allergens to determine if their is reproducibility, or if expired allergens result in differing rates of irritant reactions. (i.e. Nickel sulfate allergen was shown to have a 50% increased rate of irritant reactions between the expired to non-expired allergens, meaning that Nickel resulted in an irritant reaction in 6 cases of the expired Nickel and 4 cases of the non-expired Nickel, suggesting that expired Nickel allergens may become more irritating over time, resulting in more irritant reactions.
Measured: Standard patch test series are applied on Day 0. Participant remove patches on Day 2, photos taken and sent to Dermatologist for virtual reading. Final reading completed in clinic by Dermatologist on Day 4 or 5, recording reaction scores, morphology.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Aug 2026
- Study startSep 2026 (estimated)
- Primary completionDec 2027 (estimated)
- Study completionDec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (9)Papers the sponsor has linked to this study.
- Other trials for Allergic Contact DermatitisStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Diagnosis
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- All participants will receive patch testing with both the expired and non-expired patches.
- Masking
- None (open label)
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Calgary
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Laurie Parsons, University of Calgary
- Investigators
- Laurie Parsons, Medical Doctor, Principal investigator, University of Calgary
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07765563
- Sponsor's protocol ID
- REB26-0539
- Status last verified
- Jul 2026
- First submitted
- 7 Jul 2026
- Last updated
- 14 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Aside from eventual publication of study results to help guide practice, we will not be sharing granular study data with other researchers for expansion of the study.
Publications
Houle MC, DeKoven JG, Atwater AR, Reeder MJ, Warshaw EM, Pratt MD, Belsito DV, Adler BL, Silverberg J, Yu J, Botto N, Mowad CM, Dunnick CA, Taylor JS. North American Contact Dermatitis Group Patch Test Results: 2021-2022. Dermatitis. 2025 Sep-Oct;36(5):464-476. doi: 10.1089/derm.2024.0474. Epub 2025 Apr 24.
PubMed 40274377Schalock PC, Dunnick CA, Nedorost S, Brod B, Warshaw E, Mowad C, Scheman A; American Contact Dermatitis Society Core Allergen Series Committee. American Contact Dermatitis Society Core Allergen Series: 2020 Update. Dermatitis. 2020 Sep-Oct;31(5):279-282. doi: 10.1097/DER.0000000000000621.
PubMed 32947457Siegel PD, Fowler JF, Law BF, Warshaw EM, Taylor JS. Concentrations and stability of methyl methacrylate, glutaraldehyde, formaldehyde and nickel sulfate in commercial patch test allergen preparations. Contact Dermatitis. 2014 May;70(5):309-15. doi: 10.1111/cod.12169.
PubMed 24731086Mowitz M, Svedman C, Zimerson E, Bruze M. Fragrance patch tests prepared in advance may give false-negative reactions. Contact Dermatitis. 2014 Nov;71(5):289-94. doi: 10.1111/cod.12300. Epub 2014 Sep 18.
PubMed 25231568Mose KF, Andersen KE, Christensen LP. Stability of selected volatile contact allergens in different patch test chambers under different storage conditions. Contact Dermatitis. 2012 Apr;66(4):172-9. doi: 10.1111/j.1600-0536.2011.02035.x.
PubMed 22404192Goon AT, Bruze M, Zimerson E, Sorensen O, Goh CL, Koh DS, Isaksson M. Variation in allergen content over time of acrylates/methacrylates in patch test preparations. Br J Dermatol. 2011 Jan;164(1):116-24. doi: 10.1111/j.1365-2133.2010.10087.x.
PubMed 21039407Johansen JD, Aalto-Korte K, Agner T, Andersen KE, Bircher A, Bruze M, Cannavo A, Gimenez-Arnau A, Goncalo M, Goossens A, John SM, Liden C, Lindberg M, Mahler V, Matura M, Rustemeyer T, Serup J, Spiewak R, Thyssen JP, Vigan M, White IR, Wilkinson M, Uter W. European Society of Contact Dermatitis guideline for diagnostic patch testing - recommendations on best practice. Contact Dermatitis. 2015 Oct;73(4):195-221. doi: 10.1111/cod.12432. Epub 2015 Jul 14.
PubMed 26179009Rodrigues Barata AR, Haroun-Diaz E, Conde-Salazar Gomez L. Can expired TRUE Test(R) be used for patch testing? Contact Dermatitis. 2014 Jun;70(6):381-2. doi: 10.1111/cod.12175. No abstract available.
PubMed 24846590Mahajan VK, Chauhan PS, Mehta KS, Sharma A, Chowdhary B, Dhattarwal N, Sharma H, Chandel M, Verma YR. Patch testing with expired Indian patch test kits: Results of a pilot study. Indian J Dermatol Venereol Leprol. 2022 Mar-Apr;88(2):188-195. doi: 10.25259/IJDVL_390_19.
PubMed 33969657
Study at a glance
From the registry record, last updated by the sponsor on 14 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Reliability of Expired Allergens in Patch Testing: A Comparative Study With Non-Expired Series
- ClinicalTrials.gov ID
- NCT07765563
- Acronym / sponsor ID
- REB26-0539
- Conditions
- Allergic Contact Dermatitis
- Keywords
- contact dermatitis, patch testing
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- University of CalgaryUniversity, hospital or other
- Study start
- Sep 2026 (estimated)
- Primary completion
- Dec 2027 (estimated)
- Study completion
- Dec 2027 (estimated)
- First posted
- 14 Aug 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Patch testing remains the gold standard in the diagnosis of allergic contact dermatitis. Patches used in testing consist of a wide spectrum of allergens, with variability in the stability of products over time. Due to limited allergen stability, careful storage and preparation is needed to prevent product degradation over time. Expiration dates are provided by manufacturers to ensure stability and reactivity, while minimizing the risk of product degradation contributing to inaccurate testing results. Preparation of patch series can be time intensive and procurement of allergens comes with an associated economic burden. Expired allergens are not routinely used in patch testing, however many clinics have expired allergens accessible. There is paucity of evidence comparing the reactivity of expired vs non-expired patch series. If expired allergens remain effective, this could result in significant cost-savings and accessibility implications for dermatology practice.
Detailed description
In brief, review of the medical literature showed two comparable studies out of India and Spain suggesting that expired allergen series may be used beyond their labeled expiry dates, with some variability noted amongst duration of expiry, that the investigators will also aim to analyze.
Regarding allergen stability, there were also several studies focused on this domain. The European Society of Contact Dermatitis (ESCD) released guidelines in 2015, outlining optimal methods for allergen storage such as storage at 4 degrees celsius and strict protection from ultraviolet light exposure. While most allergens are dispersed in petrolatum (white soft paraffin), some substances are better tested in solutions such as water (aqueous) or ethanol. Several allergens with high vapour pressure require more frequent renewal and strict storage conditions such as fragrance chemicals, acrylates and isocyanates. Other substances such as glutaraldehyde in petrolatum (pet.) and formaldehyde in aqueous solution (aq.) are susceptible to instability and deterioration. An additional study assessed volatility over time of several select compounds and described high volatility in acrylates, glutaraldehyde, and fragrances, while describing partial volatility of formaldehyde and low volatility of nickel sulfate.
Study participants will include all eligible adults seen in patch testing clinic who maintain an indication for patch testing and consent to participation. The study will be utilizing 10 allergens from the North American Contact Dermatitis Group (NACDG) 80 Series for inclusion in the study.
The allergen selections are primarily based on compounds with a higher likelihood for volatility, in addition to inclusion of two comparator compounds with lower volatility. Expiration intervals include 1 year, 2 years, 3 years, and 4 years. The compounds selected are as follows, including their dispersion compound: nickel sulfate hexahydrate (5% pet.), cobalt (II) chloride hexahydrate (2.5% pet.), hydroperoxides of linalool (1% pet.), hydroperoxides of limonene (0.3% pet.), fragrance mix 1 (8.0% pet.), myroxylon pereirae resin (balsam of Peru) (25.0% pet.), methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) (0.02% aq.), formaldehyde (2.0% aq.), tixocortol-21-pivalate (1.0% pet.), and budesonide (0.1% pet.).
The patch testing results will be compared to corresponding non-expired allergens from the same manufacturer with the same preparation tested simultaneously. Both series will be placed simultaneously in differing locations on the participant's back, ensuring both are placed in sun protected areas with no underlying dermatitis.
Once in clinic, standard patch test series are applied on patch testing day, with the participant instructed not to shower or scratch the area throughout testing. At 48h, the patches are removed and photos are taken of the participant's back which are sent to the Dermatologist for virtual reading. At either 96h or 120h, the participant returns to the clinic for final reading. Both morphology and intensity of positives are graded on a standard patch test scale (irritant reaction), +/- for doubtful, + for erythema and infiltration, ++ for edematous or vesicular and +++ for spreading, bullous or ulcerative. Positive allergens scored + or greater are considered a true allergic contact allergen and assessed for relevance based on clinical context. The Dermatologist provides information sheets on all positive allergens, counsels on the relevance to their clinical history and allergen avoidance going forward, as well as providing the participant with a safe product list via the ACDS Contact Allergen Management Program (CAMP) database.
The investigators are aiming for enrolment of 100 participants which should theoretically provide the study with at least 5-10 participants testing positive to each of the four listed allergens with higher volatility and 20+ participants testing positive to the allergens with lower volatility. The investigators are aiming to assess concordance between expired and non-expired allergen reactions (positive vs negative), in addition to agreement in reaction intensity, differences in morphology, rates of false positives/negatives compared to control and concordance of irritant reaction between interventions.
The study will serve to lend valuable evidence as to whether expired allergens maintain clinical utility and could serve to reduce product waste, lower the economic burden and further improve accessibility of patch testing for use in resource limited settings.
Study design
- Primary purpose
- Diagnosis
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- All participants will receive patch testing with both the expired and non-expired patches.
| Arm | Type | Receives |
|---|---|---|
| Enrolled Study Participants | Other | Biological: Patch 1 (Expired), Biological: Patch 2 (non-expired)All enrolled participants will be simultaneously patch tested with both expired and non-expired patches. Therefore, there is no difference in intervention amongst study participants. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Adults (age 18 years or older) referred for patch testing.
Key exclusion criteria (4 listed)
- Relative or absolute contraindication to patch testing
- Wide spread dermatitis prior to patch placement
- Inability to return to clinic for reading of results
- Patient non-consenting
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Patch 1 (Expired)All enrolled participants will be simultaneously patch tested with both expired and non-expired patches. Therefore, there is no difference in intervention amongst study participants. | Biological | Enrolled Study Participants |
| Patch 2 (non-expired)All enrolled participants will be simultaneously patch tested with both expired and non-expired patches. Therefore, there is no difference in intervention amongst study participants. | Biological | Enrolled Study Participants |
Primary outcome
Patch Testing Response (Positive/Negative) Concordance Rate (%) Between Non-Expired and Expired Allergens
Time frame: Standard patch test series are applied on Day 0. Participant removal of patches on Day 2 and self photos taken and sent to Dermatologist for virtual reading. Final reading completed in clinic by Dermatologist on Day 4 or 5, recording reaction scores.
Each allergen will be graded on response using a standard patch test scale including: irritant reaction ['IR'], '+/-' for doubtful, '+' for erythema and infiltration, '++' for edematous or vesicular and '+++' for spreading, bullous or ulcerative response that will be graded by the participating Dermatologist. Reactions graded '+', "++", or "+++" are consider a positive result. Concordance rate will be expressed as a percentage (%) between tested allergens that were non-expired and that were expired (i.e. Nickel sulfate hexahydrate was found to have a 92% concordance rate, meaning that in 92% of cases, the Nickel allergen in the non-expired and expired patches were both found to both be either positive or negative while in 8% of cases the response differed per the scale listed above.)
3 secondary outcomes
Reaction/Morphology Scoring Concordance (%)
Time frame: Standard patch test series are applied on Day 0. Participant remove patches on Day 2, photos taken and sent to Dermatologist for virtual reading. Final reading completed in clinic by Dermatologist on Day 4 or 5, recording reaction scores, morphology.
Stability Concordance (%) Amongst Mediums
Time frame: Standard patch test series are applied on Day 0. Participant remove patches on Day 2, photos taken and sent to Dermatologist for virtual reading. Final reading completed in clinic by Dermatologist on Day 4 or 5, recording reaction scores, morphology.
Irritant Reaction Rates (%)
Time frame: Standard patch test series are applied on Day 0. Participant remove patches on Day 2, photos taken and sent to Dermatologist for virtual reading. Final reading completed in clinic by Dermatologist on Day 4 or 5, recording reaction scores, morphology.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Aug 2026.
- Results publication: PubMed 40274377Houle MC, DeKoven JG, Atwater AR, Reeder MJ, Warshaw EM, Pratt MD, Belsito DV, Adler BL, Silverberg J, Yu J, Botto N, Mowad CM, Dunnick CA, Taylor JS. North American Contact Dermatitis Group Patch Test Results: 2021-2022. Dermatitis. 2025 Sep-Oct;36(5):464-476. doi: 10.1089/derm.2024.0474. Epub 2025 Apr 24.
- Results publication: PubMed 32947457Schalock PC, Dunnick CA, Nedorost S, Brod B, Warshaw E, Mowad C, Scheman A; American Contact Dermatitis Society Core Allergen Series Committee. American Contact Dermatitis Society Core Allergen Series: 2020 Update. Dermatitis. 2020 Sep-Oct;31(5):279-282. doi: 10.1097/DER.0000000000000621.
- Results publication: PubMed 24731086Siegel PD, Fowler JF, Law BF, Warshaw EM, Taylor JS. Concentrations and stability of methyl methacrylate, glutaraldehyde, formaldehyde and nickel sulfate in commercial patch test allergen preparations. Contact Dermatitis. 2014 May;70(5):309-15. doi: 10.1111/cod.12169.
- Results publication: PubMed 25231568Mowitz M, Svedman C, Zimerson E, Bruze M. Fragrance patch tests prepared in advance may give false-negative reactions. Contact Dermatitis. 2014 Nov;71(5):289-94. doi: 10.1111/cod.12300. Epub 2014 Sep 18.
- Results publication: PubMed 22404192Mose KF, Andersen KE, Christensen LP. Stability of selected volatile contact allergens in different patch test chambers under different storage conditions. Contact Dermatitis. 2012 Apr;66(4):172-9. doi: 10.1111/j.1600-0536.2011.02035.x.
- Results publication: PubMed 21039407Goon AT, Bruze M, Zimerson E, Sorensen O, Goh CL, Koh DS, Isaksson M. Variation in allergen content over time of acrylates/methacrylates in patch test preparations. Br J Dermatol. 2011 Jan;164(1):116-24. doi: 10.1111/j.1365-2133.2010.10087.x.
- Results publication: PubMed 26179009Johansen JD, Aalto-Korte K, Agner T, Andersen KE, Bircher A, Bruze M, Cannavo A, Gimenez-Arnau A, Goncalo M, Goossens A, John SM, Liden C, Lindberg M, Mahler V, Matura M, Rustemeyer T, Serup J, Spiewak R, Thyssen JP, Vigan M, White IR, Wilkinson M, Uter W. European Society of Contact Dermatitis guideline for diagnostic patch testing - recommendations on best practice. Contact Dermatitis. 2015 Oct;73(4):195-221. doi: 10.1111/cod.12432. Epub 2015 Jul 14.
- Results publication: PubMed 24846590Rodrigues Barata AR, Haroun-Diaz E, Conde-Salazar Gomez L. Can expired TRUE Test(R) be used for patch testing? Contact Dermatitis. 2014 Jun;70(6):381-2. doi: 10.1111/cod.12175. No abstract available.
- Results publication: PubMed 33969657Mahajan VK, Chauhan PS, Mehta KS, Sharma A, Chowdhary B, Dhattarwal N, Sharma H, Chandel M, Verma YR. Patch testing with expired Indian patch test kits: Results of a pilot study. Indian J Dermatol Venereol Leprol. 2022 Mar-Apr;88(2):188-195. doi: 10.25259/IJDVL_390_19.
- Individual participant dataSharing planned: No. Aside from eventual publication of study results to help guide practice, we will not be sharing granular study data with other researchers for expansion of the study.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Laurie Parsons, Medical Doctor principal investigator
University of Calgary
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Patch 1 (Expired) and Patch 2 (non-expired) in people with Allergic Contact Dermatitis, run by University of Calgary at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 14 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Dylan Hollman, Medical Doctor (1-403-955-8444, dylan.hollman@ucalgary.ca), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Patch Testing Response (Positive/Negative) Concordance Rate (%) Between Non-Expired and Expired Allergens (time frame: Standard patch test series are applied on Day 0. Participant removal of patches on Day 2 and self photos taken and sent to Dermatologist for virtual reading. Final reading completed in clinic by Dermatologist on Day 4 or 5, recording reaction scores.). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07765563, which also lists 9 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 14 Aug 2026.