Dear members,

Please find below brief summaries of recent publications of interesting, including a systematic review on the effect of JAK inhibitors on patch testing, and a case of an unusual source of chromium ACD.

Janus Kinase Inhibitors’ Effect on Patch Testing: A Systematic Review

Gratz BW, Chung S, Hussain AN. Dermatitis. 2026 Feb 17:17103568261415887. doi: 10.1177/17103568261415887.

This systematic review examines Janus kinase (JAK) inhibitors influence on patch test results. Eight studies (35 patients: 21 upadacitinib, 10 abrocitinib, 2 baricitinib, 2 tofacitinib) were included. Heterogeneity of study design limited quantitative meta-analysis. Majority (32 patients) were tested on full-dose treatment; 3 underwent patch testing after washout period (2 for 2 weeks, 1 unspecified duration). Of 32 patients with paired patch testing (results before and during JAK inhibitor treatment), 71.9% converted to entirely negative results on repeat testing. Some strong (2+ or 3+) reactions persisted, whereas other reactions were attenuated from strong (2+ or 3+) to weak positive or doubtful reactions. However, new weak positive reactions were also observed despite testing on JAK inhibitors. The authors conclude that clinicians should interpret patch test results cautiously in patients taking JAK inhibitors and to consider washout period of 2 weeks prior to patch testing.

Higher Prevalence of Contact Sensitization to Dodecyl Gallate in Patients With Atopic Dermatitis: A Cross-Sectional Study

Zaryczańska A, Sokołowska-Wojdyło M, Wilkowska A, Grubska-Suchanek E, Nowicki RJ, Trzeciak M. Dermatitis. 2026 Mar 1:17103568261427111. doi: 10.1177/17103568261427111.

Gallates are antioxidant preservatives widely used in cosmetics and foods, with dodecyl gallate considered the most allergenic derivative. Colleagues in Poland conducted a cross-sectional study (2023-2024) evaluating the prevalence of contact sensitisation to dodecyl gallate in patients with atopic dermatitis (AD) compared with non-atopic controls. Sensitisation was significantly more frequent in AD [20.0% (n=16/80) vs 7.5% (n=6/80), OR 3.08, p = 0.037]. This was particularly in children (13.6% vs 0%, p = 0.026) but not in adults nor was there correlation with severity of AD. Fifteen patients improved with avoidance of dodecyl gallate (13 AD, 2 without AD). The authors conclude that dodecyl gallate is an under-recognised allergen and recommend considering this allergen, especially in patients with persistent eczema.

Uncommon Source of Chromium Sensitization: Allergic Contact Dermatitis From Potassium Dichromate in Milk Adulteration Testing

Sharma A, Mittal AK, Balai M. Contact Dermatitis. 2026 Mar 2. doi: 10.1111/cod.70127.

This paper reports a 26-year-old female presenting with eczematous areas on both arms caused by exposure to potassium dichromate in the laboratory conducting milk adulteration testing, highlighting an unusual source of chromium sensitisation. Patch testing elicited strong positive (++) reaction to potassium dichromate 0.5% pet. The authors report that potassium dichromate is used in certain laboratory-based milk adulteration testing as oxidising reagent and indicator, albeit reducing in use. Other non-construction sources of chromium include laboratory reagents, photography chemicals, and industrial oxidising agents. This study emphasizes the need for awareness of unexpected exposure sources of chromium.