Contact allergy to methylchloroisothiazolinone/methylisothiazolinone in north-eastern Italy: a temporal trend from 1996 to 2016.

BACKGROUND: Methylchloroisothiazolinone (MCI)/methylisothiazolinone (MI) (Kathon® CG) is a common preservative used in industrial products, owing to its strong biocide effect. Contact allergy to MCI/MI has been reported in different occupations, including mechanics, hairdressers and healthcare workers. OBJECTIVE: To retrospectively analyse the temporal trend of MCI/MI sensitization in north-eastern Italy and to evaluate the associations with occupations in our geographical area. METHODS: From 1996 to 2016, 27 381 patients with suspected allergic contact dermatitis were patch tested in eight departments of Dermatology or Occupational Medicine in north-eastern Italy. Individual characteristics were collected through a standardized questionnaire. RESULTS: The overall prevalence of MCI/MI sensitization was 4.2%, with the highest prevalence found in women and in patients younger than 25 years. MCI/MI sensitization was significantly associated with atopic eczema (OR: 1.34, 95% CI: 1.10-1.70), hand/forearm dermatitis (OR: 1.20, 95% CI: 1.05-1.36) and face dermatitis (OR 1.30, 95% CI: 1.10-1.40). There was a significant association between MCI/MI sensitization and chemical processing workers (OR 1.74, 95% CI: 1.03-2.94), while mechanics and healthcare workers resulted more sensitized to this hapten only in the last 3 years. CONCLUSION: Sensitization to MCI/MI is rising in the last years in Triveneto region, the 'epidemic' of sensitization to MCI/MI is mainly driven by extra-occupational dermatitis, and sensitization in some occupational groups is emerging only in the last years. A full labelling is compulsory for all products that contain isothiazolinones, to permit to identify the culprit agent.

Diaminodiphenylmethane Sensitization in north-eastern Italy from 1996 to 2012.

BACKGROUND: 4,4'-Diaminodiphenylmethane (DDM) is an aromatic amine used as a hardener, insulator and anticorrosive. Exposure implies risk of being sensitized and developing contact dermatitis. OBJECTIVE: The aim of this study was to determine the occurrence of contact sensitization to DDM among patients with contact dermatitis and the role of occupational exposure. PATIENTS AND METHODS: From 1996 to 2012, 24 056 consecutive patients with suspected allergic contact dermatitis were patch tested in north-eastern Italy. Individual characteristics were collected through a standardized questionnaire in eight departments of dermatology and occupational medicine. RESULTS: The overall prevalence of DDM sensitization was 2.5% (n = 599) with a decreasing trend in considered years. Trieste area had the higher prevalence of sensitization (3.2%). Mechanics and chemical industry workers had a significant higher risk of being sensitized to DDM. CONCLUSION: DDM sensitization is decreasing in years and is associated with some occupational exposures.

Healthcare workers and skin sensitization: north-eastern Italian database.

BACKGROUND: Working in healthcare is regarded as a risk factor for occupational skin disease. Workers are exposed to disinfectants, soaps, detergents and latex and need to wash their hands frequently and thoroughly. AIMS: To investigate the association between healthcare work and patch test reactions to various potential sensitizers in a population of contact dermatitis patients in various dermatology and occupational medicine units in north-eastern Italy. METHODS: Patients with suspected allergic dermatitis underwent patch testing. Odds ratios (ORs) and 95% confidence intervals (CIs), adjusted by age and sex, were calculated for healthcare workers (HCWs), using white-collar workers as control group. RESULTS: HCWs represented 14% of the sample of 19088 patients (68% women, 32% men). Among HCWs, both sexes had a higher risk of developing hand/forearm dermatitis (females: OR 2.1, 95% CI 1.8-2.5; males: OR 1.6, 95% CI 1.3-2.1). HCWs had an increased risk of sensitization to formaldehyde (OR 1.65; 95% CI 1.2-2.3) and to p-phenylenediamine (OR 1.6; CI 1.1-2.3). CONCLUSIONS: Our study suggests a significant association between healthcare work, hand/forearm dermatitis and sensitization to formaldehyde and p-phenylenediamine.

Differences in clinicopathological features and distribution of risk factors in Italian melanoma patients.

BACKGROUND: No studies are available in the literature on the distribution of different melanoma features and risk factors in the Italian geographical areas. OBJECTIVE: To identify the differences in clinical-pathological features of melanoma, the distribution of risk factors and sun exposure in various Italian macro-areas. METHODS: Multicentric-observational study involving 1,472 melanoma cases (713 north, 345 centre, 414 south) from 26 referral centres belonging to the Italian Multidisciplinary Group for Melanoma. RESULTS: Melanoma patients in northern regions are younger, with thinner melanoma, multiple primaries, lower-intermediate phototype and higher counts of naevi with respect to southern patients; detection of a primary was mostly connected with a physician examination, while relatives were more involved in the south. Northern patients reported a more frequent use of sunbeds and occurrence of sunburns before melanoma despite sunscreen use and a lower sun exposure during the central hours of the day. CONCLUSIONS: The understanding of differences in risk factors distribution could represent the basis for tailored prevention programmes.

Diaminodiphenylmethane (DDM): frequency of sensitization, clinical relevance and concomitant positive reactions.

Diaminodiphenylmethane (DDM) is an aromatic diamine used in the manufacture of rubber, plastics, diisocyanates, dyes and adhesives. It may cross-react with para-(amino)compounds. Allergic patch test reactions to DDM are relatively frequent, but their relevance is often difficult to detect. We report our experience in 6809 patients (4589 female, 2220 male, mean age 39.9+/-17.8 years) with suspected contact dermatitis patch tested during the period 1997-1999 by the North-East Italy Contact Dermatitis Group (NEICDG). A positive patch test to DDM was detected in 132 (1.9%) patients (88 female, 44 male, mean age 49.5+/-16.2 years). Eczema was mostly localized on the hands. The relevance was detected in 31 patients. A logistic regression analysis showed an association with patient's age (odds ratio 5.4 for age 30-59 years), absence of atopic diseases (odds ratio 3.1) and presence of leg ulcer (odds ratio 5). We found a highly significant correlation (p<0.001) between sensitivity to DDM and to para-phenylenediamine, Disperse Yellow 3, cobalt chloride, fragrance mix, benzocaine, paraben mix and primin. Positive patch test results to DDM were relatively frequent. The difficulty in detecting the relevance of these sensitizations may be related to the surprisingly high frequency of concomitant positive reactions to other allergens.