Dear members,

This month’s edition selection covers the diverse causes and clinical presentation of chronic hand eczema, skin penetration and lipid effects of fragrance terpene hydroperoxides, the prevalence and clinical relevance of formaldehyde contact allergy, and an occupational case of allergic contact dermatitis caused by disperse dyes in paint.

Moderate to Severe Chronic Hand Eczema in Clinical Practice: Etiological Subtypes, Clinical Signs and Symptoms, and Comorbidities—Results From the RWEAL Study.

C. Fargnoli, S. Molin, A. Bewley et al. Journal of Dermatological Treatment. 2026; 37(1): 2603121.

This multinational chart review included 1,939 adults with moderate-to-severe chronic hand eczema (CHE) across six countries. Irritant contact dermatitis was the most common aetiological subtype (40.1%), followed by atopic dermatitis (33.1%) and allergic contact dermatitis (27.5%), with the latter more common in patients with severe disease. More than one subtype was identified in 14.2% of patients. The palms, fingertips and backs of the hands were most frequently affected, and erythema, pruritus and scaling were the most common clinical features. A history of atopic dermatitis was reported in 43.8%, supporting CHE as a heterogeneous condition with multiple possible aetiologies rather than simply atopic dermatitis affecting the hands

Absorption and Effects of Patch Test Preparations of Hydroperoxides of Limonene and Hydroperoxides of Linalool in Human Ex Vivo Skin.

A. Clancy, L. Hagvall, P. Malmberg and N. M. O’Boyle, Contact Dermatitis. 2026; 95: 159–168,

This ex vivo study used Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) imaging to examine the skin penetration of patch test preparations of hydroperoxides of limonene 0.3% and linalool 1.0%, and their effects on skin lipids. After 24 hours, both hydroperoxides were largely confined to the stratum corneum, with lower levels detected in the viable epidermis. Hydroperoxides of linalool altered levels of several stratum-corneum lipids, including cholesterol, monoacylglycerols, diacylglycerols and phosphatidylcholines. Similar trends were observed with hydroperoxides of limonene, although changes in individual lipid species did not reach statistical significance. Overall, the findings indicate that fragrance terpene hydroperoxides are absorbed into human skin and can alter its lipid composition, particularly within the stratum corneum, although the clinical significance remains uncertain.

The Prevalence of Contact Allergy to Formaldehyde and Formaldehyde Releasers: A Systematic Review and Meta-Analysis.

K Karimian, D. Isufi, M. B. Jensen et al. Contact Dermatitis. 2026; 95: 125–147,

This systematic review and meta-analysis of 158 studies involving over 1.3 million dermatitis patients found a pooled prevalence of formaldehyde contact allergy of 2.88%, with 41.6% of positive reactions considered clinically relevant. Among formaldehyde releasers, sensitisation was highest to 2-bromo-2-nitropropane-1,3-diol (2.76%) and quaternium-15 (1.89%), the latter having the highest clinical relevance (55.7%). Prevalence varied geographically, being highest in North America (6.8%) compared with Europe (2.3%) and Southeast Asia (1.8%), but did not differ significantly by age or atopic dermatitis status. Overall, formaldehyde and its releasers remain relevant contact allergens, with substantial regional variation potentially reflecting differences in regulation and exposure.

Occupational Allergic Contact Dermatitis in a Wall Painter: Identification of Disperse Yellow as the Causative Agent.

Rozas LM, Andreu-Barasoain MI, Valdés AM, Estebaranz JLL. Contact Dermatitis. 2026 Aug;95(2):223-226.

This case report describes occupational allergic contact dermatitis in a 47-year-old wall painter exposed to industrial paints containing Disperse Yellow dyes. Patch testing showed strong reactions to PPD and a textile dye mix, with further testing identifying positive reactions to Disperse Yellow 3 and Disperse Orange 1 and 3. Disperse Yellow dyes were identified in work paints; symptoms recurred after unprotected paint exposure. Episodes of unilateral facial dermatitis associated with his partner’s use of PPD-containing hair dye, which resolved when the partner stopped using it, consistent with connubial allergic contact dermatitis. The case highlights disperse dyes as potential occupational allergens in paint and the importance of considering indirect household exposure.