We present the largest clinical experience with the European photopatch test baseline series hitherto reported. The results are similar to those underlying the above consensus process, reaffirming the usefulness of this series.
Background
Since 2009, an increasing number of published cases of allergic contact dermatitis (ACD) from isothiazolinones in Europe was observed, amounting to an epidemic. However, only few studies have assessed the current situation after changes in European regulation.
Objectives
To analyze the incidence of isothiazolinone‐related ACD in our area in the last decade.
Methods
A retrospective study analyzed all patients patch tested in the allergy unit in a tertiary hospital in Spain between January 2010 and June 2019. Positive patch‐test reactions to methylchloroisothiazolinone (MCI)/methylisothiazolinone (MI) and/or MI alone were recorded.
Results
A total of 243 patients (9.55%) with positive patch‐test reactions to MCI/MI and/or MI alone among 2544 consecutively patch‐tested patients were recorded. An initial increase in the prevalence of MCI/MI allergy was observed, from 4.5% in 2010 reaching a peak in 2015, which was followed by a significant decrease until July 2019 with 3.1% prevalence in 2019.
Conclusions
As shown in our data, regulatory interventions have resulted in a dramatic decrease in the prevalence of MCI and MI ACD, reaching a pre‐epidemic level of 3.1% in 2019.
We present 7 cases of postsurgical contact dermatitis due to povidone iodine. The diagnosis was based on the clinical manifestations, the history of exposure, the site of the lesions, and the results of patch tests. This type of dermatitis can develop in the area of surgery or at distant sites exposed to povidone iodine during the surgical intervention. Patch tests with 10% povidone iodine in petrolatum were positive in all patients. Based on the results of the same tests in a control group, we recommend the use of petrolatum rather than water as the vehicle for the diagnosis of this form of contact dermatitis. Repeated open application tests with a commercially available solution of povidone iodine were negative. We conclude that the presence of the solution under occlusion during surgery is necessary both for the symptoms to develop and for the diagnosis to be made. This condition may be underdiagnosed.
Chlorhexidine is one of the most widely used antiseptics in our environment. Allergic contact dermatitis to chlorhexidine is common in adults, but is quite rare in the pediatric population. Its diagnosis is important because it can mimic other dermatoses common during childhood, and it can also lead to acute immediate hypersensitivity | 541 Pediatric Dermatology BRIEF REPORT undiagnosed. 1 Only 4 cases have been reported of ACD to chlorhexidine in pediatric patients without underlying AD. 3-5 Darrigade et al reported the largest case series of pediatric patients with ACD to chlorhexidine. Epicutaneous patch testing for chlorhexidine digluconate was positive in 7 of 14 patients tested, whereas 8 of them exhibited positivity to benzyl alcohol and positivity to both allergens in 4 cases. 1Our work showcases the role of chlorhexidine as a cause for ACD in the pediatric population, especially, but not exclusively, among patients with AD. It is worth noting that a history of surgery at an early age was identified in one patient suggesting the possibility that sensitization had occurred then. We emphasize the clinical utility of ROAT as a simple initial diagnostic approach during the initial evaluation of a patient presenting with symptoms suggestive of ACD to chlorhexidine. The different commercial formulations of this antiseptic must be taken into account, as some regularly used excipients, such as benzyl alcohol, which can also cause ACD. 1 Furthermore, we must inform parents that chlorhexidine is not only present in antiseptic products but also as a component of cosmetics. 2 Last but not least, it is imperative to rule out immediate hypersensitivity reactions, as even mild cases of ACD can indicate a potential risk of acute hypersensitivity reactions following successive exposures to chlorhexidine. 6
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