Dear members,

Summarised below are 4 recent publications, including a study examining allergens in toothpastes marketed in the UK, analysis of extracts from diabetic devices as well as prevalence in sensitisation to disperse blue 124.

The importance of comprehensive patch testing: A call to action from the American Contact Dermatitis Society.
Chen JK, Atwater AR, Belsito DV, Ehrlich A, Taylor JS, Yu J, Flamm A, Brod B. J Am Acad Dermatol. 2025 Nov 27:S0190-9622(25)03280-3.

This American Contact Dermatitis Society (ACDS) call to action urges clinicians and healthcare services ensure availability of comprehensive patch testing (up-to-date screening series, supplementary panels, and individualised allergens) for accurate diagnosis of allergic contact dermatitis (ACD). They highlight data by Houle et al. showing that the 35-allergen T.R.U.E Test may miss 39.6 – 47.7% of allergens identified by the 80-allergen NACDG series. They highlight that by even using the NACDG series alone, clinically important allergens may be missed in around 21% of patients. Furthermore, supplementary panels enable early recognition of emerging allergens and change in allergen trends.  The ACDS emphasises that equitable access to a broad number of commercially available allergens is a public health priority.

Mint condition? A Survey of Allergenic Ingredients in UK Toothpastes
Phillips PF, Rogers A, Soriano LF. Clin Exp Dermatol. 2026 Jan 8:llag006.

The authors examined ingredients present in toothpastes from 5 major UK cosmetics suppliers. Of 291 products, 286 (99%) contained fragrances, frequently labelled non-specifically as “aroma”. Limonene was found in 159 (55%) and menthol-related compounds in 105 (36.3%). The most frequent identified preservatives were sodium benzoate/benzoic acid. Polyaminopropyl biguanide, banned in cosmetics, was declared in 3 (1%). Tin salts, an increasingly recognised cause of allergic cheilitis, were present in 31 products, either as stannous fluoride in 21 (7.3%) or stannous chloride in 10 (3.5%). Two products lacked ingredient listing. This study highlights the importance of considering allergens in toothpastes in diagnostic assessment of patients with oral symptoms and signs.

Results of GC-MS Analyses of 40 Extracts of Diabetes Devices.
van Oers EM, de Groot AC, Verolme P, Ipenburg NA, Rustemeyer T. Contact Dermatitis. 2025 Nov 28.

This study aimed to identify the chemical composition of diabetes devices. The authors performed gas chromatography-mass spectrometry (GC-MS) on 40 acetone extracts from 27 devices (10 glucose sensors, 3 patch pumps, 12 infusion sets, 2 adhesives), identifying 284 distinct chemicals. Every extract contained at least one established allergen. Over half of the products (52%) contained acrylates, 30% contained colophonium derivatives, all devices contained one or two of the phenolic allergens (2,4 di tert butylphenol, p tert butylphenol or butylated hydroxytoluene) and one third contained 1-hydroxycyclohexyl phenyl ketone. Bisphenol A was detected in 50% of extracts, and in two cases it was present in extremely high quantities. Only one product (Accu-Chek SmartGuide) contained isosorbyl acrylate (IBOA). This study highlights that the composition of diabetic devices is changing. All products investigated contained known sensitising chemicals. Important allergenic chemicals now present are the phenolic compounds, 1-hydroxycyclohexyl phenyl ketone and possibly the non-IBOA acrylates.

Sensitization to Disperse Blue Dye 124 in Triveneto Region from 1997 to 2021 and Its Potential Occupational Role.
Zampa N, Romanelli S, Belloni Fortina A, Giulioni E, Cegolon L, Larese Filon F. Life (Basel) 2025 Nov 5;15(11):1711. doi: 10.3390/life15111711. PMID: 41302135; PMCID: PMC12653182.

This large multicentre retrospective study analyses sensitisation to Disperse Blue 124 1% pet based on data from 30, 639 patients tested in North-East Italy between 1997 and 2021. Overall prevalence of sensitisation was 2.5%. Similar to other studies, the authors report a clear decline over time, falling from >3.5% in the late 1990s to 1.5 – 1.9% in recent years, likely reflecting reduced use of this dye in modern textiles. Sensitisation was more common in women and in patients aged 35-65 years, with facial involvement relatively frequent. Occupational cases were unusual, with higher rates observed in textile workers (5.8%) and painters (3.9%). Disperse blue 124-associated contact dermatitis is declining but remains relevant for monitoring given prevalence remains >1%.

Abstract submission for the annual BAD meeting closes soon! For those wishing to submit abstracts to both the BAD main meeting as well as the BSCA Special Interest Group meeting, datelines for submission are as follows:

Abstract submission deadlines

Main Meeting – Midnight on Friday 9th January 2026
Special Interest Groups – Midnight on Friday 6th February 2026

Please check the website for further details: https://badannualmeeting.co.uk/

Dear members,

Below are brief summaries of 3 recent studies examining ingredients in henna, complimentary hotel products and allergen sensitisation in woodworkers as well as a case report on a ‘hidden allergen’ in baby wipe product.

Consumer Risk in Henna Use: Labeling, Ingredients, and Allergen Disclosure

Bouchelkia I, Alam Z, Annamalai A, Verma KK, Tarbox MB, Desai SR, Bhatia N. Consumer Risk in Henna Use: Labeling, Ingredients, and Allergen Disclosure. Int J Dermatol. 2025 Nov 21. doi: 10.1111/ijd.70165. Epub ahead of print. PMID: 41273067.

This study looked at 36 henna products marketed to U.S consumers and found that PPD was only disclosed in 11% of items examined. Many products were marketed with “natural/organic” claims, with incomplete ingredient lists. Of those where PPD was declared, a recurring excipient triad of tartaric acid, sodium sulfite and cellulose binders were present. Most items provided vague or absent patch-test instructions and explicit adverse reaction descriptions were rare. Although European cosmetic standards generally require clearer labelling of known sensitizers and more explicit safety information than current US regulations, this study highlights the need for clinicians maintain a high index of suspicion for henna-related ACD, routinely screen for recent henna exposure, and counsel patients that “natural” labelling does not ensure safety.

Epidemiological Comparative Study on Contact Sensitisations in Woodworkers With Occupational Dermatitis: Patch Test Data of the Information Network of Departments of Dermatology, 1999 to 2023.

Heizmann L, Schubert S, Bauer A, Becker D, Brockow K, Dickel H, Kränke B, Lang C, Oppel E, Wagner N, Weisshaar E, Wilfinger D, Brans R; IVDK. Epidemiological Comparative Study on Contact Sensitisations in Woodworkers With Occupational Dermatitis: Patch Test Data of the Information Network of Departments of Dermatology, 1999 to 2023. Contact Dermatitis. 2025 Nov 12. doi: 10.1111/cod.70041. Epub ahead of print. PMID: 41224355.

This large IVDK analysis spanning 24 years (1999-2023) examined 471 woodworkers with occupational dermatitis (OD). Allergic contact dermatitis was the most frequent diagnosis (32.5%), with frequent involvement of the hands (63.5%) and the face (8.5%). Sensitisation to epoxy resins was significantly greater compared to woodworkers without OD (sensitisation frequency 5.5% versus 1.3%). Despite colophonium similarly frequently testing positive (5.3% vs 1.9%), this did not reach significant threshold. As airborne ACD from colophonium in sawdust has been reported, the authors considered this as probably contributary to those with facial dermatitis.
Other allergens in affected woodworkers included: Myroxylon pereirae (6.9%), methylisothiazolinone (5.9%), and methyldibromo glutaronitrile (5.6%). Propolis was the only significantly more frequently positive allergen compared to non-woodworkers with OD (5.6% versus 2.5%). These findings highlight the importance of including baseline, resin/glue and plant-based series, considering airborne allergic contact dermatitis and promoting suitable personal protective equipment.

A Cross-Sectional Study of Contact Allergens in Hotel Personal Care Products in Canada, the United States and Europe.
Viltakis V, Kirchhof MG. A Cross-Sectional Study of Contact Allergens in Hotel Personal Care Products in Canada, the United States and Europe. Contact Dermatitis. 2025 Nov 21. doi: 10.1111/cod.70057. Epub ahead of print. PMID: 41267567.

This cross-sectional study analysed ingredient lists from 270 complimentary hotel personal care products (shampoos, conditioners and body washes) from 90 hotels across Canada, the United States and Europe, identifying presence of American Contact Dermatitis Society (ACDS) core allergens. Fragrance was almost ubiquitous across all regions (96.7–100% of products), but preservatives showed marked geographic variation. MCI/MI was a common allergen in US (40%) and Canadian (47.8%) hotel products compared to only 4.4% of European products (p<0.0001). DMDN hydantoin, a formaldehyde releaser, was detected in approximately one in seven products in US/Canada but was not present in any European products. More stringent regulation in Europe has resulted in decrease in ACD to MCI/MI and MI, in comparison to North America. Travellers should be alert to differences in product ingredients in different regions.

Axillary Contact Dermatitis in an Adult Caused by Hexamidine Diisethionate From Baby Wipes Labelled “Pure Water”.

Domingos-Ancement EE, Misery L, Deydier N. Axillary Contact Dermatitis in an Adult Caused by Hexamidine Diisethionate From Baby Wipes Labelled “Pure Water”. Contact Dermatitis. 2025 Nov 19. doi: 10.1111/cod.70055. Epub ahead of print. PMID: 41261938.

This case report describes a rare instance of axillary and facial allergic contact dermatitis in a 51-year-old man caused by hexamidine diisethionate in baby wipes marketed as “pure water”. Standard patch testing was negative for hexamidine, but a repeated open application test (ROAT) with the wipes was positive on day 3. This case report highlights that marketing claims do not always match product ingredient lists and that hexamidine diisethionate can be present in baby wipes.

Dear members,

To limit the number of emails received via forum posts, the monthly Bitesize Updates will be posted under the News section from now on. This will also enable easy reference to previous Bitesize Updates as well. We have included here 4 recent publications which may be of interest:

Virtual Reality Headset as a Cause of Allergic Contact Dermatitis in a Child

Eid D, Akhtar S, Stone N (October 19, 2025) Virtual Reality Headset as a Cause of Allergic Contact Dermatitis in a Child. Cureus 17(10): e94906. doi:10.7759/cureus.94906

Our colleagues in Newport report the first paediatric case of virtual reality (VR) headset-associated ACD. A 13-year-old boy presented with persistent periorbital and upper cheek eczematous change, areas in direct contact with his VR headset (Oculus Quest 2, Meta Platforms). Extensive patch testing elicited a reaction to: MI, MCI/MI, benzisothiazolinone (BIT), Bronopol, methyldibromoglutaronitrile, propolis, Carba Mix, and to foam from the headset itself. As chemical analysis was not performed, presence and relevance of all allergens could not be confirmed. Use of silicone cover in place of the foam resulted in complete resolution. This case highlights that wearable-devices can be a cause of ACD and the importance of inclusion of device material in diagnostic patch testing.

Positive Patch Test Reaction to Sodium Metabisulfite: Prevalence, Relevance and Clinical Implications

Casciola G, Stingeni L, Bianchi L, Agostinelli D, Tramontana M, Hansel K. Positive Patch Test Reaction to Sodium Metabisulfite: Prevalence, Relevance and Clinical Implications. Contact Dermatitis. 2025 Nov 5. doi: 10.1111/cod.70050. PMID: 41194600

Sodium metabisulfite (SMB) is widely found as a preservative in cosmetics, food/beverage and drugs such as epinephrine (adrenaline)-containing local anaesthetics. Attribution of relevance of SMB patch test reactions can be difficult due to ubiquitous presence in products. This retrospective study from Perugia, Italy assessed 16 SMB patch test positive patients (prevalence 2.9% of 550 tested patients) between January 2024 and April 2025. Fourteen of these had strong or extreme reactions on day 4. No clinical relevance was identified in any of the 16 patients. Delayed-reading intradermal testing (IDT) with SMB 1% in saline was performed, followed by challenge with dermal injections of 0.9mL (0.1 mL, 0.3 mL, and 0.5 mL at 30 minute intervals) of mepivacaine and epinephrine containing 0.025% SMB if negative on IDT. All tested negative on intradermal and challenge test. Findings from this study suggests high prevalence without clear relevance to SMB and positive patch test may not contraindicate systemic exposure, such as though local anaesthetic administration.

 Caprylyl Glycol, a Trending and Highly Relevant Sensitiser in Cosmetics That Needs to be Patch Tested Separately

Kanokrungsee S, Dendooven E, Aerts O. Caprylyl Glycol, a Trending and Highly Relevant Sensitiser in Cosmetics That Needs to be Patch Tested Separately. Contact Dermatitis. 2025 Nov;93(5):418-421. doi: 10.1111/cod.70019. Epub 2025 Aug 26. PMID: 40855841.

Alternative preservatives, termed ‘para-preservatives’ are increasingly used in cosmetics and personal care products in place of traditional preservatives. One such preservative, caprylyl glycol (CG) (1,2-octanediol) has rarely been reported to cause ACD. Retrospective analysis of a 4-year period (January 2021 – December 2024) from a single centre in Antwerp identified 9 positive CG patients, predominantly affecting the face (n=5). Initial testing was performed with 5% pet obtained from a cosmetic company and subsequently with 1% pet due to limited availability. Prevalence on testing to both concentrations was 0.77% and 0.12%, at the 5% and 1% concentrations respectively. CG was present in patients’ products in 8 cases, with all improving with avoidance of identified allergens. Three of the products were labelled as being ‘hypoallergenic’. Concominant allergy to propylene glycol (PG) was not common despite similar structure as only 2 patients tested positive to PG as well. This study shows CG is an emerging allergen, particularly in cosmetics and ‘hypoallergenic’ items, and testing with 5% pet should be considered.

Nickel Contact Allergy in an Australian Patch Testing Centre Over 2014-2023

Brasher TR, Palmer A, Nixon R. Nickel Contact Allergy in an Australian Patch Testing Centre Over 2014-2023. Australas J Dermatol. 2025 Oct 25. doi: 10.1111/ajd.14611. Epub ahead of print. PMID: 41137537.N

Nickel is a common cause of ACD and unlike the European Union where there is regulation regarding presence of nickel in items in prolonged contact with skin, no such legislation exists in Australia. The Skin Health Institute in Melbourne conducted a retrospective audit spanning 10 years, showing a prevalence of 16.0% (573 of 3582 patients), whereby 4.7% were deemed relevant and 11.8% due to occupation causes. There was an overall trend of reduced relevance of patch test positive patients over the period despite stable prevalence. Occupation-related nickel ACD was comparable to 11.7% prevalence in 1993-2010 reported by the centre previously. Despite the decrease in assessed relevance of nickel patch test positive reactions, no clear cause of this was identified although the authors considered the possibility of reduction in amount of nickel in consumer products such as in coins.

New Patient Information Sheets have been published by the BSCA:

• Tosylamide/Epoxy resin
• Phthalic Anhydride/Trimellitic Anhydride/Glycols Copolymer
• Adipic Acid/Neopentyl Glycol/TrimelliticAnhydride Copolymer

We hope you will find these useful in counselling your patients.

BSCA Committee

The Patient Information Leaflets Update Group have been working on improving several of the information leaflets to ensure these are up-to-date. Updated information sheets for the following allergens can now be found on the BSCA PILs page:

• Cetearyl alcohol
• Cobalt
• Gallates
• Potassium dichromate

We hope you will find these useful in counselling your patients.

BSCA committee

An online SCE revision session jointly organised by the British Society for Medical Dermatology (BSMD) and British Society for Cutaneous Allergy (BSCA) will be held for trainees from 7-8pm on Wednesday 1st October.

The session is free for members of BSCA/BSMD and is question-based for attendees to test their knowledge on a range of topics on contact dermatitis. High-yield facts essential for preparation for the exam will be covered.

If not already a member, register for BSCA membership in advance of the session by visiting https://cutaneousallergy.org/membership/. 

As membership processing can take several weeks, do ensure you join as a member soon as otherwise may not receive the link for the session when it is circulated at the end of September.

The BSCA-Dowling Club update meeting will be taking place on 26-27th September. A range of topics relevant to contact dermatitis, including recent allergens to be aware of. Last remaining places available so register soon to secure a place!

To register: https://www.eventsforce.net/bad/509/home

The BSCA-Dowling Club update meeting will be taking place in Crewe on 26-27th September. Places are filling up therefore register early to avoid disappointment!

To register: https://www.eventsforce.net/bad/509/home

In response to concerns raised about clinicians offering patch testing services that may not meet the existing service standards, the Cutaneous Allergy Service Standard Working Party Group will be reformed. The group will update the existing standards and explore ways of monitoring and enforcing these for the British Association of Dermatologists (BAD) both in the public and private sectors.

A patch testing standard operating procedure that was co-authored with the British Dermatological Nursing Group (BDNG) has been uploaded to the BSCA website: https://cutaneousallergy.org/resources/patch-testing-guidance-and-standards/. This should allow departments to set up and benchmark their patch test service against current standards.