Photoaggravated allergic contact dermatitis and transient photosensitivity caused by methylisothiazolinone.

BACKGROUND: Photoaggravated allergic contact dermatitis caused by methylchloroisothiazolinone (MCI)/methylisothiazolinone (MI) and MI has been reported. OBJECTIVES: To describe the clinical characteristics and results of (photo)patch tests and photo-tests of 10 patients in Belgium and France suffering from photoaggravated contact dermatitis caused by MI. PATIENTS AND METHODS: Five men and five women, with a median age of 49.5 years, were investigated between January 2012 and February 2017 because of suspected photoaggravated contact dermatitis. Patch tests, photopatch tests and/or photo-tests were performed. RESULTS: Seven patients had positive patch test reactions to both MCI/MI and MI, whereas 3 patients had positive patch test reactions only to MI. In most cases, MI was the (strong) primary sensitizer. Photopatch tests with MCI/MI and/or MI gave stronger reactions than patch tests with these derivatives, indicating photoaggravation. Sensitization probably took place from cosmetics and work-related biocides, whereas elicitation of dermatitis was remarkably often related to airborne exposure to MI present in paints or industrial biocides. Four patients suffered from transient photosensitivity. CONCLUSION: Photoaggravated allergic contact dermatitis and transient photosensitivity caused by MI is a peculiar clinical presentation of allergic contact dermatitis caused by this preservative, and should be considered in daily clinical practice.

Outbreak of contact sensitization to methylisothiazolinone: an analysis of French data from the REVIDAL-GERDA network.

BACKGROUND: The preservative methylisothiazolinone (MI) is used in combination with methylchloroisothiazolinone (MCI), but the MCI/MI mixture has been identified as highly allergenic. MI is considered to be less allergenic, and since the mid-2000s has been widely used alone, but is now clearly identified as a contact allergen. The French Vigilance Network for Dermatology and Allergy of the Study and Research Group on Contact Dermatitis (REVIDAL-GERDA) added MI to its baseline patch testing series in 2010. OBJECTIVE: To evaluate the change in the proportion of MI-positive tests in France between 2010 and 2012. PATIENTS/MATERIALS/METHODS: We conducted a nationwide, multicentre, retrospective study of all MI-tested patients between 2010 and 2012. RESULTS: Sixteen centres participated in the study (7874 patients were tested). Patch tests were performed mainly at a concentration of MI 200 ppm aq. We observed a significant increase in the proportion of MI-positive tests in 2012 and 2011 as compared with 2010 (5.6%, 3.3%, and 1.5%, respectively; p < 0.001). CONCLUSIONS: We report a significant increase in the number of MI-positive tests. MI is confirmed to be a rapidly emerging allergen, as also observed in other European countries.

The European Standard Series and its additions: are they of any use in 2013?

This study has two purposes:--to know whether the European standard series is still the key reference when it comes to contact dermatitis, i.e., are its components still the most frequently involved allergens in contact dermatitis nowadays?--to assess the results of the European standard series among French and Belgian dermatologists/allergists as, so far, most of them have failed to provide statistical data within the European community of allergists/dermatologists. 18 participants from 2 dermatology and allergy centres in Belgium and 11 centres in France collected their results from 3,073 patients tested in 2011. They assessed the relevance of some tests as well as that of the standard series and additional series to establish an etiological diagnosis of contact dermatitis. These results, together with the history of the European standard series, have shown that some allergens are obsolete and that others should be included in a new standard series for which we are making a few suggestions.

Parabens: a real hazard or a scare story?

Parabens belong to a family of preservatives that are widely used, particularly in the cosmetic, pharmaceutical and food industries. Four esters are commonly used: methyl, ethyl, propyl and butyl parabens. They are either used alone or, for better efficacy, in the form of a mixture. They have been the target of a media smear campaign since 2005. Several studies have failed to formally prove their alleged responsibility in the occurrence of breast cancer. At recommended concentrations, methyl and ethyl parabens have no hormonal effect in humans. Propyl and butyl parabens are still being investigated as regards their effects on fertility in men exposed during early childhood. Parabens are well-known for having weak sensitising properties and for their absence of toxicity whereas new substitution products, not as well-known, may lead to new cases of contact allergy.

Globalisation and allergy.

Globalisation brings patients more and more into contact with products or food from other cultures or countries. Europeans may be confronted with allergens not yet known in Europe - such as dimethylfumarate - responsible for contact allergy epidemics. Moreover, "low cost" goods, not always legally imported into Europe, sometimes may lead to European legislation being circumvented and thus bring our patients into contact with components that have been banned from manufacturing processes or strongly regulated, such as nickel in jewelry or telephones, some colouring agents in clothes or preservatives in cosmetics. Disinfection measures for freight containers arriving from other continents into our harbours lead to fumigants and other toxic products contaminating the air and the transported products or goods. Globalisation can not only elicit contact allergy but also airborne contact dermatitis or food allergy. The aim of this paper is not to make an exhaustive review of cutaneous allergic problems elicited by globalisation, but to illustrate this new worldwide problem with a few meaningful examples.