Dear members,

Summarised below are a few recent publications including case reports on allergic contact dermatitis to headphones and sunscreen products which we hope will be of interest.

Allergic Contact Dermatitis in Children Over a 20-Year Period: A Danish Single-Centre Study

Herlin LK, Bregnhøj A, Sommerlund M. Contact Dermatitis. 2026 Sep 16. doi: 10.1111/cod.70241.

This 20-year Danish single-centre study examined patterns of allergic contact dermatitis in 721 children and adolescents patch tested between 2005 and 2024. In additional to baseline series, extra allergens, such as acrylate allergens, were tested based on clinical history. Results were additionally analysed across 4 consecutive 5-year periods. Overall, 34.4% had at least one positive patch test, predominantly to metals (7.8-13% for nickel, cobalt, chromate) followed by methylisothiazolinone (3.6%). Clinical relevance was identified in 49.6% of positive reactions. While the prevalence of positive patch tests remained relatively stable (29-37% in each 5-year period), the findings highlight emergence of acrylate allergy with 11.9% testing positive (12 of 101 tested patients). The authors emphasise the importance of continued patch testing in children and adapting allergen testing panels to reflect changing exposures.

Allergic Contact Dermatitis From Hearing Aid Ear Moulds: Different Devices, Different (Meth)acrylate Sensitization Profiles

G. Guzmán-Perera, A. Goossens, O. Aerts, and E. F. García-Perez. Contact Dermatitis 95, no. 5 (2026): 523–525,

Guzmán-Perera et al. report a case of allergic contact dermatitis caused by hearing aid ear moulds, with positive patch test reactions to tetrahydrofurfuryl methacrylate (THFMA) in addition to other acrylates (HPMA, TMPTA, HEMA) and scrapings from the ear moulds. Neither THFMA nor HEMA were listed on the ingredient list of the ear moulds. Similar finding of positive THFMA reactions have previously been reported by Ipenburg et al. (https://doi.org/10.1111/cod.70228.) in 8 patients with suspected allergic reactions to ear moulds. Whether THFMA sensitisation reflects primary sensitisation, cross-reactivity with other (meth)acrylates or exposure to an undeclared constituent remains uncertain. These findings reinforce the importance of considering hearing aid materials as a potential cause of persistent ear canal dermatitis and testing should ideally be by integrating manufacturer-specific material composition with targeted (meth)acrylate patch testing.

Occupational Allergic Contact Dermatitis From Over-Ear Headphones: Chemical Analysis Reveals Octylisothiazolinone and Other Potential Skin Sensitizers

Fenech, E. Langlois, E. Pelletier, C. Champmartin, L. Bensefa-Colas, and M.-N. Crepy. Contact Dermatitis (2026): 1–9.

There are emerging reports of allergic contact dermatitis (ACD) associated with over-ear headphones, particularly due to octylisothiazolinone (OIT). Fenech et al. report two cases of occupational ACD with positive patch test reactions to OIT. Chemical analysis confirmed presence of OIT in both sets of headphones, including 10 of 11 samples from parts of one pair and also identified benzisothiazolinone (BIT) in 5 samples from the same pair. Other potential allergens detected included isobornyl acrylate (IBOA), rubber accelerators, plasticisers, benzoyl peroxide and dimethylformamide. Both patients’ dermatitis resolved following avoidance of the headphones, highlighting considering headphone materials as potential cause of occupational and non-occupational ear dermatitis.

Multiple Allergic Contact Sensitizations to UVA Sunscreen Filters Including Methoxypropylamino Cyclohexenylidene Ethoxyethylcyanoacetate (Mexoryl 400)

Badaoui. Contact Dermatitis (2026): 1–3.

This case report describes a patient who experienced recurrent eczematous flares following application of several sunscreen products, with patch testing demonstrating concomitant sensitisation to multiple UV filters: methoxypropylamino cyclohexenylidene ethoxyethylcyanoacetate (Mexoryl 400, also known as MCE), terephthalylidene dicamphor sulfonic acid (Mexoryl SX) and butyl methoxydibenzoylmethane (avobenzone) in addition to triethanolamine. Four sunscreens used by the patient contained the identified allergens. Mexoryl 400 is a relatively recent UVA1 filter, with a prior case of ACD reported in 2025. The author considered the positive reactions to represent co-sensitisation, given lack of structural similarities between the identified allergens. This case reinforces the need to consider individual UV filters and other sunscreen ingredients when investigating suspected ACD caused by sun protection products.