Methylisothiazolinone allergic contact dermatitis: Assessment of relapses in 139 patients after avoidance advice

Abstract

Background Methylisothiazolinone (MI) is a preservative that is responsible for an epidemic of allergic contact dermatitis (ACD). Few studies have been published on the prognosis of patients with MI‐induced ACD. Objectives To evaluate relapses of MI‐induced ACD and difficulties in avoiding MI in patients who had received avoidance advice. Methods A retrospective study of patients with MI‐induced ACD diagnosed in two specialized dermato‐allergology units between 2010 and 2015 was performed. The median follow‐up was 3 years. Results Relapses were observed in 64% of 139 included patients, and were severe in 18%. Rinse‐off cosmetics were responsible for the largest proportion of relapses (27%). The median time to relapse was 5 months. Sixty‐nine per cent of relapses were on the hands, and 29% were on the face. Risk factors for relapsing were hand eczema and a personal history of atopy. The main difficulties encountered in the avoidance strategy were hidden sources of MI, the lack of labelling on industrial products, the complexity of cosmetic labelling, and remembering the name of the allergen. Conclusion MI‐induced ACD has a poor prognosis. Its high rate of relapse is mainly attributable to the difficulties of avoidance. Management needs to be improved. Specialized follow‐up in the year following diagnosis is essential to educate patients.

Methylchloroisothiazolinone/methylisothiazolinone and methylisothiazolinone contact allergy: A 24‐year, single‐center, retrospective cohort study from Turkey

“…However, a long-term follow-up was missing, and relapses might be expected due to new exposure to isothiazolinone-containing rinse-off cosmetics, incomplete labelling of some products, and hidden sources, as previously reported. 67 In 2018, the Committee for Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH) in the European Union decided that industrial products, such as paints and detergents, must bear the warning, "Contains methylisothiazolinone. May cause an allergic skin reaction", when they contain more than 15 ppm MI.…”

Allergy to isothiazolinones in recent years

“…Bouschon i wsp. zwracają uwagę na złe rokowanie u pacjentów z alergicznym kontaktowym zapaleniem skóry wywołanym izotiazolinami [23]. U 64% z 139 chorych wystąpiły nawroty, w tym u 18% o ciężkim przebiegu [23].…”

“…Szkodliwe działanie wykazywały nie tylko kosmetyki pozostawiane na skórze, ale i spłukiwane. Te ostatnie były odpowiedzialne za 27% nawrotów alergicznego kontaktowego zapalenia skóry [23].…”

“…towarzyszącą alergię na inne związki chemiczne. Stwierdzono uczulenie na nikiel u 48,7% badanych, na środki zapachoweu 34,6% [23]. Wyniki badań przeprowadzonych przez autorki potwierdzają te spostrzeżenia.…”

Contact Allergy—Emerging Allergens and Public Health Impact

“…The beneficial impact of an adequate diagnosis of contact allergy-in this case, to MI-is illustrated by a study evaluating the QoL before diagnosis and at 3-months follow-up after diagnosis of MI contact allergy, finding a highly significant improvement [115]. However, particularly with more long-term follow-up, relapses despite counselling are not infrequent and mostly related to hidden sources of MI, the lack of labelling on industrial products, the complexity of cosmetic labelling, and remembering the name of the allergen [116]. A Thai study found that widespread dermatitis, seen in 20.2% of 3201 patients, demonstrated that preservatives were the significant offending allergens, especially MCI/MI and MI alone [117].…”