The dramatic increase in the rate of methylisothiazolinone contact allergy in Belgium: a multicentre study.

BACKGROUND: The rate of contact allergy and allergic contact dermatitis caused by methylisothiazolinone (MI) is dramatically increasing throughout Europe. OBJECTIVES: To report on methylchloroisothiazolinone (MCI)/MI and MI allergy in Belgium. PATIENTS AND METHODS: Between January 2010 and December 2012, the medical charts of 6599 patients of the Belgian Contact and Environmental Dermatitis Group were retrospectively reviewed for MCI/MI and MI sensitization by use of a standardized questionnaire. Available data on sensitization in 2081 patients tested in 2013 were also included. RESULTS: In 2012, the sensitization rate for MCI/MI had increased to 4.5% and that for MI to 6.0%; the latter showed a further increase to 7.2% in 2013. The people mainly affected were women with a median age of 49 years with hand and/or facial dermatitis, most often resulting from the use of cosmetics. Simultaneous reactions to octylisothiazolinone were observed. CONCLUSION: A dramatic increase in the rate of contact allergy caused by MI in cosmetics is occurring in Belgium. Notwithstanding the recent recommendation to discontinue the use of MI in leave-on cosmetics, safer use concentrations should also be determined for rinse-off products. Close monitoring of MI sensitization in the near future will be necessary, and the highest test concentrations reported for MI and MCI/MI should be included in the baseline series.

Occupational airborne contact dermatitis from benzodiazepines and other drugs.

BACKGROUND: Healthcare workers (or relatives) crushing drug tablets for patients with difficulties in swallowing are at risk of developing sensitization via airborne exposure. Tetrazepam, in particular, is increasingly being described as an important occupational allergen in this regard, although other drugs are also involved. OBJECTIVES: To identify the allergenic culprits in 4 patients, namely 2 nurses, 1 pharmacy assistant, and 1 spouse, who all regularly crushed tablets of systemic drugs and presented with severe airborne dermatitis. METHODS: The patients were patch tested with all of the drugs that they handled, as well as with potential cross-sensitizing molecules. RESULTS: All 4 patients reacted to tetrazepam and other benzodiazepines, some of which they had not previously come into contact with, which favours cross-reactivity rather than concomitant sensitization. These patients also had positive reactions to several other non-structurally related drugs for which, in some cases, there was no history of exposure. CONCLUSIONS: Subjects having to crush drugs, in either an occupational or a non-occupational context, and who present with dermatitis suspected of being airborne-induced, should be patch tested with all contacted medicaments, as well as with possible cross-reacting molecules. Prevention by the use of crushing devices and protective measures (gloves and masks) when medications are handled should be advised.

Relevance of positive patch-test reactions to fragrance mix.

BACKGROUND: Fragrances are an important cause of allergic contact dermatitis. We presume that the traditional fragrance mix (FM) detects 70 to 80% of fragrance-allergic patients. FM has an irritant potential. Weak positive reactions may have a greater chance of being irrelevant than strong reactions. OBJECTIVE: To improve the appraisal of FM patch-test reactions, we studied the relevance of reactions of different strength. We also studied the predictive value of the following on the relevance of the initial FM patch-test results: patch-test results of a repeated FM test; results of patch tests with balsam of Peru, colophony, and ingredients of the mix; and (history of) atopic dermatitis. METHODS: One hundred thirty-eight patients who had doubtful positive (?+) or positive (+ to +++) reactions were included in the study. We determined relevance by history taking, location and course of the dermatitis, and additional patch testing. Patients were retested with FM and with each ingredient separately. RESULTS: The relevance of reactions to FM increases with the strength of the reactions. Predictors of relevance are the results of retesting with FM, the results of tests with the ingredients, and a history and/or present symptoms of atopic dermatitis. CONCLUSION: Retesting with FM and its ingredients may add to the benefit of patch testing.