- Contact dermatitis has two main types. Irritant dermatitis is a direct injury to the outer skin layer and is the more common type. Allergic contact dermatitis is an immune reaction and is less common (NHS).
- Patch testing is the NHS's main way to find an allergic trigger. Allergens are left on the skin for 2 days, then read again 2 days later, because most allergic reactions take that long to appear (NHS diagnosis page). DermNet says patch testing is "not useful in investigating irritant dermatitis" (DermNet).
- Patch tests have real limits. Coloured allergens can stain the skin and be mistaken for a true positive, and a negative result may mean the dermatitis is irritant or endogenous, or that the allergen was never tested (DermNet).
- Barrier creams and moisturisers may help prevent work-related hand dermatitis, but we could not establish that from the sources we could read. A 2022 JMIR Dermatology letter comments on a Cochrane review of interventions for occupational irritant hand dermatitis; we could not open its conclusions or effect estimates, so no figures are given here (JMIR Dermatology letter).
- Steroid creams are graded by potency. DermNet places them in potency classes, says potent steroids are "best avoided" on thin skin such as the eyelids, genitals and skin creases, and lists skin thinning among the effects of prolonged use (DermNet steroids).
- Fragrance and preservatives are regulated, but not completely. The European Commission's scientific committee identifies 82 established contact allergens in humans. The EU fragrance labelling list was 26 substances (Annex III) until Regulation (EU) 2023/1545 expanded it to about 80 entries, applying from 31 July 2026 to newly placed products (EC scientific committee; the 2023 amendment is described from secondary summaries). Regulation (EU) 2016/1198, of 22 July 2016, bans methylisothiazolinone in leave-on cosmetics and allows up to 100 ppm in rinse-off products (Regulation (EU) 2016/1198).
- Money trail: the FDA lists the Rubber Panel T.R.U.E. Test with SmartPractice Denmark ApS as manufacturer, but its page for the general T.R.U.E. Test names Mekos Laboratories AS, so the maker name needs checking per product (FDA listing). The North American benchmark record we retrieved shows no funding statement, and its full text was not opened. Chemotechnique, a Swedish maker of patch-test products, gives its founding year and certifications on its website but does not state its ownership (Chemotechnique).
- Evidence grade: Strong that irritant and allergic dermatitis need different handling and that patch testing is for allergic causes. Insufficient for barrier creams and gloves in prevention. Moderate for steroid potency guidance. Risk from mis-read patch tests and from long-term potent steroid use.
Independent evidence review · Skin condition
Contact dermatitis is a skin reaction to something touched, and the split between irritant and allergic causes decides the test and the treatment. UK public-health guidance and clinical references agree on that split. Patch testing finds allergic triggers but is not useful for irritant dermatitis, and it can mislead when read carelessly. Barrier creams and moisturisers may help at work, but we could not establish a benefit from the sources we could read. Our confidence is high on the irritant-versus-allergic split and on patch-test limits. It is low on product claims, because the patch-test panel evidence we could open is either maker-linked or has no funding statement.
Table of contents
- Evidence summary
- What contact dermatitis is
- How the two types develop
- What works and what does not
- Benefits and claims, one by one
- Risks and side effects
- Confounders and test interactions
- Who needs specialist review
- Steroid potency and how it is used
- Follow the money: who makes the panels and who funded the evidence
- Related research
- Frequently asked questions
- Sources and funding notes
Evidence summary
| Claim | Evidence | Source | Funding / conflict | Strength |
|---|---|---|---|---|
| Irritant and allergic contact dermatitis are different conditions | Public-health descriptions of both types and common triggers | NHS | Public health service; funding statement not opened | Strong |
| Patch testing identifies allergic triggers | Clinical reference and national guidance describe patch testing as the main method | NHS diagnosis; DermNet | Neither page states its funder in the text we read | Moderate |
| Patch testing does not help with irritant dermatitis | Stated directly in clinical reference material | DermNet | Funder not stated | Strong |
| Barrier creams prevent occupational irritant hand dermatitis | Not established from the sources we could read; the Cochrane review's conclusions were not opened | JMIR Dermatology letter | Letter's disclosure statement and the review's funding not read | Insufficient |
| Moisturisers prevent occupational hand dermatitis | Not established from the sources we could read | JMIR Dermatology letter | As above | Insufficient |
| Protective gloves prevent contact dermatitis at work | Not established from the sources we could open | JMIR Dermatology letter | As above | Insufficient |
| Potent steroids should be used with care on thin skin and for limited periods | Potency classes and warnings in clinical reference; no trial reviewed | DermNet steroids | Funder not stated | Moderate |
| Long-term potent steroid use can cause skin damage | Listed effects: thinning, striae, bruising, steroid rosacea, periorificial dermatitis | DermNet steroids | Funder not stated | Risk |
| Fragrance allergens are numerous and only partly labelled | Scientific committee opinion: 82 established allergens; the labelling list was 26 substances until Regulation (EU) 2023/1545 expanded it to about 80 | EC scientific committee | EU public body; the opinion date is not stated on the page we read | Strong |
| Methylisothiazolinone is banned in leave-on cosmetics | Binding EU regulation citing scientific committee advice | Regulation (EU) 2016/1198 | Statutory measure; not a funded study | Strong |
| Nickel release limits for jewellery and skin-contact items | We could not open the primary legal text to check the limit | None opened | Not applicable | Insufficient (not verified) |
Independent evidence and credibility scorecard
Tier legend: Tier 1 independent (no identifiable financial stake in the outcome); Tier 2 indirect or unknown ties; Tier 3 interested party (trade body, advocacy group, competitor); Tier 4 self-interested (maker, seller or promoter). Credibility A high, B solid with bias to watch, C interested, D self-interested.
| Source | Who funds it | Country | Independence tier | Credibility | Why it would tell the truth / residual bias |
|---|---|---|---|---|---|
| NHS patient information | Publicly funded health service; funding statement not opened | UK | Tier 1 (independent) | B | Public health duty to patients and no sales stake. Residual bias: short patient-leaflet detail. |
| HSE INDG233 (workplace contact dermatitis) | UK government regulator; funding statement not checked | UK | Tier 1 (independent) | A | Legal accountability for workplace safety. Residual bias: guidance is not graded evidence; the leaflet was not re-read in this check and is used only as context. |
| JMIR Dermatology 2022 letter (Abdel Azim et al.) on a Cochrane review of occupational irritant hand dermatitis | Not verified: the letter's disclosure statement and the review's funding could not be read | Not verified (author institutions not checked) | Tier 2 (unknown ties) | C | A journal commentary on a Cochrane review, not the review itself; its conclusions could not be checked here. Residual bias: undisclosed ties until the disclosure statement is read; a commentary adds no independent check. |
| EC scientific committee fragrance opinion (layman summary) | EU budget, via the European Commission (funding line not checked) | EU | Tier 1 (independent) | A | Advisory role to the Commission with no sales stake. Residual bias: the layman page does not state its literature cut-off, so currency is unverified. |
| Regulation (EU) 2016/1198 | Statutory EU measure | EU (copy on UK legislation site) | Tier 1 (independent) | A | Legally binding and enforced. Residual bias: political compromise; rinse-off products kept MI at up to 100 ppm. |
| DermNet NZ clinical reference | Funder not stated on the pages read | New Zealand | Tier 2 (unknown ties) | B | Clinical education reputation. Residual bias: unknown funder; not a systematic review. |
| ESCD patch-testing guideline (Johansen et al., Contact Dermatitis, 2015) | Funding and disclosures not verified; full text not opened | Europe (multi-country author list) | Tier 2 (unknown ties) | B | Professional guideline with an incentive for accuracy. Residual bias: authors active in patch-test practice; possible industry links not checked. |
| NACDG patch-test results, 2017 to 2018 | No funding statement found in the record retrieved; full text not opened | USA and Canada (14 North American centres) | Tier 2 (unknown ties) | C | Large multicentre data (4,947 patients). Residual bias: unknown funding; the research network's benchmarks are used to judge a maker's panel. |
| FDA listing, Rubber Panel T.R.U.E. Test | Manufacturer: SmartPractice Denmark ApS (product record); FDA's general T.R.U.E. Test page names Mekos Laboratories AS | USA (regulator) and Denmark (manufacturer) | Tier 4 (self-interested) | D | Product description supplied by the manufacturer. Residual bias: the listing is a regulatory record, but the claims are the maker's. |
| Chemotechnique Diagnostics (company website) | Ownership not stated on its website | Sweden | Tier 4 (self-interested) | D | Sells patch-test products. Residual bias: promotional; self-reported manufacturing quality claims. |
Convergence and clustering. The strongest agreement is between the NHS, the UK's HSE, DermNet and the European fragrance opinion. The NHS and DermNet pages have no shared sales stake, and both separate irritant from allergic causes. The most consequential patch-test benchmark (the NACDG comparison of a rival panel) comes from a research group whose funding statement we could not locate. Most of our Tier 1 and Tier 2 sources sit in the UK and EU, and the North American benchmark sits in one regional lens. That clustering matters because panel choice differs by region.
What contact dermatitis is
Contact dermatitis is an inflamed, itchy rash that appears where skin meets a substance. The NHS describes two types. Irritant contact dermatitis happens when a substance "directly damages the outer layer of skin", and it is the more common type. Allergic contact dermatitis happens when the immune system reacts to a substance and affects the skin, and it is less common (NHS).
The NHS lists soaps, detergents, solvents and regular water contact as common irritants. Allergen triggers it lists include cosmetics, some metals including nickel, and handling raw fruit and vegetables (NHS). The Health and Safety Executive guidance covers workplace contact dermatitis; we could not read its list of specific workplace causes or its glove and hand-washing advice from the pages available to us (HSE INDG233).
How the two types develop
The NHS describes irritant dermatitis as direct damage to the outer skin layer, and allergic dermatitis as an immune reaction (NHS).
This is why the test and the treatment differ. Patch testing looks for delayed allergic reactions (NHS diagnosis). For skin care, the NHS describes moisturisers as applied to stop the skin drying out, and recommends emollient soap substitutes rather than regular bar or liquid soaps (NHS).
What works and what does not
| Approach | What the evidence shows | Verdict |
|---|---|---|
| Patch testing for suspected allergic contact dermatitis | Described as the best way to test for allergic reactions; reads at 2 and 4 days (NHS) | Works for allergy |
| Patch testing for suspected irritant dermatitis | "Not useful" for irritant dermatitis (DermNet) | Not useful |
| Barrier creams to prevent occupational irritant hand dermatitis | Not established from the sources we could read (JMIR letter; Cochrane conclusions not opened) | Mixed, unproven |
| Moisturisers to prevent occupational hand dermatitis | Not established from the sources we could read | Mixed, unproven |
| Protective gloves | Not established from the sources we could open | No trial evidence here |
| Topical steroid creams for flares | DermNet describes potency classes and warns about long-term use | Used, with limits |
Benefits and claims, one by one
Does patch testing find the cause?
The NHS calls patch testing the best way to test for allergic reactions. Small amounts of allergens are placed on the skin, usually on the back, and sometimes on the upper arms. The patches are read after 2 days and again 2 days later (NHS diagnosis). The page we read was last reviewed on 3 May 2023, with a review due on 3 May 2026, so the page's review date had passed when we checked. DermNet says each patch tape carries 10 to 12 individual allergens, that 30 to over 100 allergens can be applied at a time, and that a baseline series picks up about 70% of contact dermatitis (DermNet).
The key point for a reader is that a positive patch test is a starting point, not a verdict. Its relevance to the person's own exposures has to be judged by a specialist who knows their history.
Can barrier creams prevent work-related hand dermatitis?
We could not establish a benefit from the sources we could read. A 2022 JMIR Dermatology letter comments on a Cochrane review of interventions for preventing occupational irritant hand dermatitis. We could not open its conclusions, effect estimates or disclosure statement, so we report no figures. A lack of demonstrated benefit in our sources is not proof of no effect, and the trial numbers would need reading directly before any product claim is made (JMIR Dermatology letter).
The sources we could open did not establish any glove effect, so we do not treat glove use as evidence of benefit.
Do steroid creams help?
DermNet describes steroid potency in classes, from mild to very potent, and says potent steroids are best avoided on thin skin (DermNet steroids). We did not review a trial of steroid potency for contact dermatitis, so this claim rests on clinical reference and is rated moderate.
Do moisturisers help the skin barrier?
The NHS advises moisturisers to stop the skin drying out, and recommends emollient soap substitutes in place of regular soap (NHS). We could not verify the moisturiser prevention figures. A pharmacist can recommend suitable products, which is a service rather than an endorsement; we name no brands.
Risks and side effects
DermNet notes that if dermatitis is very active at the time of patch testing, multiple positive patch tests may arise, sometimes called an "angry back" (DermNet patch tests). Results from an active flare are therefore harder to read, which is one reason a specialist should interpret them.
DermNet lists skin thinning (atrophy), stretch marks, and easy bruising with prolonged use of potent steroids. It also lists periorificial dermatitis and steroid rosacea as common with long-term potent use. Excessive use on eyelid skin over weeks to months may raise the risk of glaucoma or cataracts. Cushing syndrome is rarely reported, after long-term use of large amounts (DermNet steroids).
Persistent, spreading or severe rashes need a GP's review; see the clinician callout below.
Confounders and test interactions
Patch tests can be confounded in several ways that matter to a reader interpreting a result. DermNet notes that coloured allergens can stain the skin and be mistaken for a true positive. DermNet also says a negative result can mean the dermatitis is irritant or endogenous, or that the allergen was never tested (DermNet patch tests). We did not find a documented list of drug interactions for patch testing in the sources we opened, and we do not give one.
Who needs specialist review
The FDA record for the Rubber Panel T.R.U.E. Test sets an age floor of 6 years and describes it as an aid for people whose history suggests sensitivity to one or more of its five substances (FDA listing). DermNet notes that very active dermatitis can produce multiple positive patch tests, so a specialist should read the results in that case. DermNet says potent steroids are best avoided on the eyelids, genitals and skin creases (DermNet steroids). Anyone pregnant or planning pregnancy should check with a GP or pharmacist before using a potent steroid.
See a GP for persistent, spreading or severe rashes, and for any rash that does not respond to avoiding the suspected trigger. Use NHS 111 out of hours. Call 999 or go to emergency care for trouble breathing, swelling of the face, lips or throat, or widespread blistering.
This article covers a skin condition, not mental health, so no crisis-line information is included here. The NHS and emergency-service advice above is the relevant safety guidance.
Steroid potency and how it is used
We do not give personal treatment instructions. DermNet describes steroid potency in four broad classes. Very potent products include clobetasol propionate. Potent products include betamethasone valerate and mometasone furoate. Moderate products include triamcinolone acetonide. Mild products include hydrocortisone (DermNet steroids). Anyone who needs steroid treatment should follow the prescriber's or pharmacist's advice.
Product quality and patch-test panels
The FDA lists the Rubber Panel T.R.U.E. Test as made by SmartPractice Denmark ApS (FDA listing). Chemotechnique says on its own website that its haptens are produced in Sweden under GMP-based quality management, and that it holds ISO 13485 and ISO 9001 certification (Chemotechnique). Both are maker statements and are not independent quality checks.
Follow the money: who makes the panels and who funded the evidence
Who makes patch-test panels
The FDA record for the Rubber Panel T.R.U.E. Test names SmartPractice Denmark ApS as the manufacturer (FDA listing). FDA's page for the general T.R.U.E. Test names Mekos Laboratories AS instead. We did not resolve that difference, and we do not describe any parent company or ownership chain. Chemotechnique Diagnostics is a Swedish company with a registered office in Vellinge. Its website gives 1981 as its founding year and makes no statement about ownership (Chemotechnique). Both companies sell the products that patch testing uses, so both are Tier 4.
Who funded the evidence
The North American benchmark (the NACDG 2017 to 2018 results, published in Dermatitis in 2021, 14 centres, 4,947 patients, record) has no funding statement that we could find in the record or search results we retrieved. We did not open the full text, so we cannot say whether any panel maker supported it. Because this group's comparisons judge a rival panel, the undisclosed funding matters and is why we grade it C. The European patch-testing guideline (ESCD, 2015) lists its author group and affiliations (PubMed), but the funding and disclosure sections were not visible to us, so its funding is recorded as not verified. The NHS, HSE, DermNet and the European Commission pages we read did not contain funding statements in the sections we accessed.
Documented integrity events
We did not find a documented enforcement action, recall or lawsuit against the panel makers named above in the sources we opened. The 2016 EU restriction on methylisothiazolinone is a legal measure, not an integrity event (Regulation (EU) 2016/1198).
Research funding at a glance
10 sources graded. The counts below are the independence tiers assigned in the scorecard above. They count sources, not funding amounts or evidence quality.
Public funding alone does not prove independence, and commercial funding alone does not prove a claim false. Named funders, countries and relationships are in the scorecard and source notes.
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Frequently asked questions
What is the difference between irritant and allergic contact dermatitis?
Irritant dermatitis is direct damage to the outer skin layer by a substance, and it is the more common type. Allergic contact dermatitis is an immune reaction to a substance, and it is less common (NHS).
Does patch testing work?
For suspected allergic contact dermatitis, the NHS describes it as the best way to test for allergic reactions. Allergens are read after 2 and 4 days (NHS diagnosis). A positive result still needs a specialist to judge whether it is relevant to the person's history.
Can patch testing find irritant dermatitis?
No. DermNet states that patch testing is not useful for investigating irritant dermatitis (DermNet).
Do barrier creams prevent hand dermatitis at work?
We could not establish that from the sources we could read. A 2022 JMIR Dermatology letter comments on a Cochrane review, but we could not check its conclusions or effect estimates, so we give no figures here.
Are steroid creams safe to use for a long time?
DermNet warns that prolonged daily use of potent steroids can thin the skin and cause stretch marks, bruising, periorificial dermatitis and steroid rosacea. It says potent steroids are best avoided on thin skin such as the eyelids, genitals and skin creases (DermNet steroids). Ask a GP or pharmacist before long-term use.
Is fragrance in cosmetics labelled?
Partly. The European Commission's scientific committee identifies 82 established contact allergens in humans (EC scientific committee). EU labelling covered 26 fragrance substances in Annex III until Regulation (EU) 2023/1545 expanded the list to about 80, applying from 31 July 2026 to newly placed products. That amendment is described from secondary summaries, which give slightly different counts.
Is methylisothiazolinone banned in cosmetics?
It is banned in leave-on products such as wet wipes, but it is still permitted in rinse-off products up to 100 ppm under EU Regulation 2016/1198 (Regulation (EU) 2016/1198).
Who makes the patch-test panels?
The FDA lists SmartPractice Denmark ApS as the manufacturer of the Rubber Panel T.R.U.E. Test, and names Mekos Laboratories AS on its general T.R.U.E. Test page (FDA listing). Chemotechnique, a Swedish company, makes other patch-test products and states its manufacturing standards on its website (Chemotechnique).
Sources and funding notes
What we could not verify. NICE Clinical Knowledge Summaries on allergic contact dermatitis returned a 403 error, so we did not read the NICE recommendations. PubMed returned a 429 error on one search, and the Wiley full text of the 2015 ESCD guideline returned a 403 error, so its funding and disclosure sections were not read. The full Cochrane review returned a 403 error, so its conclusions and effect estimates are not reported. The JMIR Dermatology letter's full text returned no readable content on retry, so its disclosure statement, author affiliations and barrier-cream conclusions are not stated, and no pharmaceutical ties are attributed to its authors. The HSE glove and workplace-cause text could not be read from the summary page or the PDF. The EUR-Lex text of Regulation 2016/1198 could not be fetched in this check; its date (22 July 2016) is confirmed on legislation.gov.uk, and the leave-on ban and the 100 ppm rinse-off limit rest on a regulatory-news summary of the regulation. Regulation (EU) 2023/1545 is described only from secondary summaries, which give 80 to 82 entries; its primary text was not opened. The 82 count of established allergens comes from a secondary summary of the scientific committee opinion. FDA's general T.R.U.E. Test page names Mekos Laboratories AS, which conflicts with the SmartPractice Denmark ApS listing for the rubber panel; the reason was not found. A business directory listing Chemotechnique as a subsidiary of Frontier Pharma AB is unverified and not used. The nickel release limit in the EU REACH restriction could not be checked against the primary legal text, so no figure is given. We did not open the 2015 to 2016 NACDG report, so we do not quote its figures for the rival panel's missed reactions. The funding statements for the NHS, HSE, DermNet and the European Commission pages were not located in the sections we read.
- NHS, Contact dermatitis: UK public health patient information; publicly funded; funding statement not opened.
- NHS, Contact dermatitis: diagnosis: patch-testing timing and "best way" wording; last reviewed 3 May 2023 per the page.
- HSE INDG233, Preventing contact dermatitis and urticaria at work: UK regulator guidance; funder not checked; not re-read in this check.
- DermNet NZ, Patch tests: New Zealand clinical reference; author credited as Dr Ian Coulson, update December 2021; funder not stated.
- DermNet NZ, Topical steroids: potency classes and long-term risks; written 1997, updated 4 January 2016; funder not stated.
- Abdel Azim S et al., "From the Cochrane Library: Interventions for Preventing Occupational Irritant Hand Dermatitis", JMIR Dermatology 2022;5(3):e37961: commentary on a Cochrane review; disclosure statement and review funding not verified.
- Johansen JD et al., ESCD guideline for diagnostic patch testing, Contact Dermatitis 2015;73(4):195-221: professional guideline; citation and author list checked; funding and disclosures not verified.
- DeKoven JG et al., North American Contact Dermatitis Group Patch Test Results: 2017-2018, Dermatitis 2021;32(2):111-123: multicentre benchmark study; no funding statement found in the record retrieved; full text not opened.
- FDA, Rubber Panel T.R.U.E. Test: product record; manufacturer SmartPractice Denmark ApS; age 6 and over; five rubber allergens; manufacturer-supplied content. The FDA general T.R.U.E. Test page names Mekos Laboratories AS.
- Chemotechnique Diagnostics, About us: maker's own website; founding year 1981 and Vellinge address stated; ownership not stated; certifications are self-reported.
- European Commission, Scientific Committee on Consumer Safety, fragrance allergens (layman summary page): EU advisory opinion; funding line and date not verified.
- Commission Regulation (EU) 2016/1198 of 22 July 2016: statutory amendment restricting methylisothiazolinone in cosmetics; the ban on placing non-compliant products on the market applies from 12 February 2017.
- Commission Regulation (EU) 2023/1545: amends Annex III of Regulation (EC) No 1223/2009 on fragrance allergen labelling; described from secondary summaries only, primary text not opened.
Educational research reviewed 9 October 2026. This article is not medical advice; talk to a qualified clinician or pharmacist before starting, stopping or combining treatments.
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