Contact sensitization to limonene and linalool hydroperoxides in Spain: a GEIDAC* prospective study.

Limonene and linalool are common fragrance terpenes widely used in cosmetic, household and hygiene products. Their primary oxidation products formed after air exposure, the hydroperoxides, have been recognized as important contact haptens. To investigate the prevalence of contact allergy to hydroperoxides of limonene (Lim-OOHs) and hydroperoxides of linalool (Lin-OOHs) in Spain, and to define the optimal concentration for screening in consecutive patients. Three different concentrations of Lim-OOHs (0.1%, 0.2% and 0.3% pet.) and Lin-OOHs (0.25%, 0.5% and 1.0% pet.) were simultaneously tested in 3639 consecutive patients at 22 departments of dermatology in Spain. Lim-OOHs at 0.1%, 0.2% and 0.3% yielded positive patch test reactions in 1.4%, 3.4% and 5.1% of the tested patients, respectively; and Lin-OOHs at 0.25%, 0.5% and 1.0% yielded positive reactions in 1.3%, 2.9% and 4.9% of the tested patients, respectively. Few irritant (1.5-1.9%) and doubtful reactions (0.4-0.5%) to both terpene hydroperoxides were registered at the highest concentrations tested. Lim-OOHs and Lin-OOHs can be considered as common causes of contact allergy, and their inclusion in an extended baseline patch test series therefore seems to be appropriate. The patch test preparations of Lim-OOHs 0.3% pet. and Lin-OOHs 1.0% pet. are useful tools for screening of contact sensitization

Perfil epidemiológico, clínico, y alérgico en pacientes con dermatitis atópica y dermatitis de las manos. Evaluación del Registro Español de Dermatitis de Contacto (REIDAC)

BACKGROUND: Hand eczema is common in patients with atopic dermatitis (AD), but few studies have described the characteristics of these patients in large, representative populations from different geographic regions and occupational settings. OBJECTIVE: To describe the epidemiological, clinical, and allergy profile of patients with hand eczema who underwent patch testing and compare patients with and without AD. METHODS: Analysis of data from the Spanish Contact Dermatitis Registry, a multicenter registry of patients who undergo patch testing in Spain. RESULTS: We included 1466 patients with hand eczema who were patch tested between January 2018 and June 2020. Those with AD were younger and had had symptoms for longer before testing. They were also more likely to have been exposed to occupational triggers (38% vs 53% for patients without AD). The only profession for which significant differences were found was hairdressing. The most common allergens were nickel sulfate, methylchloroisothiazolinone/methylisothiazolinone, cobalt chloride, potassium dichromate, fragrance mixes I and II, and formaldehyde. The most common diagnoses were allergic contact dermatitis (24% vs 31% in patients with and without AD, P=.0224) and irritant contact dermatitis (18% and 35% respectively, P<.001). CONCLUSIONS: AD is common in patients with predominant hand eczema who undergo patch testing. Patients with hand eczema and AD have different clinical and epidemiological characteristics to hand eczema patients in general and their final diagnosis following patch testing is also different.El REIDAC ha recibido financiación de Sanofi, GlaxoSmithKline y Novartis en forma de donaciones no condicionadas. Los laboratorios financiadores no han participado en el diseño, análisis ni revisión del artícul