Insect repellents and contact sensitization: An observational study

Background: cases of allergic contact dermatitis due to insect repellents reported in the literature are rather scarce despite their widespread use. Objectives: to assess: i) the usage of insect repellents in a geographical area characterized by high presence of mosquitoes; ii) prevalence of sensitization to insect repellents; iii) potential predisposing factors; iv) concomitant sensitization to other common allergens. Methods: 106 consecutive patients were assessed for the use and type of insect repellents and their indoor/outdoor life habits. Patients were submitted to patch test with i) baseline SIDAPA series, ii) integrative Insect Repellent series. Results: 87 patients (82.07%) referred the use of insect repellents; 8 (7.55%) showed positive reactions to the integrative Insect Repellents series; sensitization was not related to gender, indoor versus outdoor occupation or hobby, atopy, kind and regular use of repellents; 7 (87.5%) patients sensitized to repellents had at least one positive reaction to allergens of the baseline series, mostly fragrances and preservatives. Conclusions: contact sensitization to ingredients contained in insect repellents is not rare, although the actual role of repellents in patient sensitization is questionable. Cosmetics and body care products may account for contact sensitization to the allergens contained in the study integrative series, mainly natural fragrances.