Introduction:

Isothiazolinones are substances widely used as preservatives and biocides in industrial, household and cosmetic products. They have been known for over 40 years as prevalent allergens that cause contact dermatitis in a professional and extra-professional context. This article reports a case of non-exclusive occupational allergic contact dermatitis.

Case report:

A 47-year-old man, industrial electrical maintenance technician for 28 years, was referred to the Dermatology Department of Hospital de Braga, due to chronic erythematous, papular and titillating lesions on the back of the hands and fingers, worsening during professional activity. It was reported by the worker a clinical improvement during periods of rest and vacations and more recent aggravation with cosmetics products for personal and domestic use. Due to suspected contact dermatitis, epicutaneous tests were performed with the standard series of the Portuguese Group for the Study of Contact Dermatitis and also three complementary series- battery of cosmetics, cutting oils and preservatives. The reading was done at 72h and revealed the following positive reactions: methylIisothiazolinone (+++); Kathon CG™ (+++) and octylisothiazolinone (+). In the follow-up of the worker, clinical improvement was obtained with the replacement of all household products and cosmetics that contained these biocides in their composition and after his occupational physician medical advice, an evaluation of industrial detergents was carried out, which confirmed the presence of isothiazolinones, that the employer promptly replaced.

Discussion/Conclusion:

After an increase of cases since the 1980s of contact dermatitis caused by isothiazolinones, the legislation has undergone several changes. However, these substances continue to play an important role, particularly at an industrial level, due to the great effectiveness they have as preservatives and biocides. In the case of this worker, the elimination of the use of all products (personal and professional) identified in its composition with sensitizing substances was the most accessible and practicable implemented measure. In occupational health, when this measure is not possible, it is necessary to implement other measures that reduce the health risk of workers through protective collective and individual equipments. It is essential to keep a constant and adequate health screenings through risk prevention programs and also promote literacy on the risk factors to which they are exposed through training workshops and information actions. Monitoring the tendency of allergic contact dermatitis to these substances continues to be relevant today.

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