Patch testing and allergic contact dermatitis in pregnancy

It is widely known that during the course of pregnancy, the body undergoes complex immunologic and hormonal shifts. As a result, immunologic processes in dermatologic disorders may change, with sometimes improving and other times worsening disease activity.1 Of the various allergic disorders that can be seen in pregnancy, allergic contact dermatitis (ACD) is less often discussed in the literature despite its relatively common prevalence among the general population.2 Current patch testing guidelines state that while there is no known risk with patch testing in pregnancy, it is recommended to be avoided as a precautionary measure.3, 4 Here, we performed a literature search to evaluate current articles discussing patch testing and ACD in pregnancy. PubMed was searched on 1 April 2024 using search keywords of 'allergic contact dermatitis', 'patch testing' and 'pregnancy'. There was no restriction on the date of publication and papers were filtered to the English language only. All articles were screened by abstract and two papers were found to satisfy criteria.1, 5 White et al. described two patients who underwent patch testing, one of whom was in the third trimester of pregnancy, and the other was a postpartum patient who was breastfeeding.5 Both patients were found to have positive reactions that then guided subsequent treatment recommendations.5 To our knowledge, this article represents the only report of patch testing in pregnancy for ACD and suggests that it could be a safe consideration if indicated. However, as the article points out, it is still questionable as to the true efficacy of performing such testing due to unclear false-positive rates that are plausible in an altered immunologic state.5 In the second article identified, Pope et al. summarized several allergic disorders seen in pregnancy.1 Interestingly, they described a disconnect in data that while ACD is more common in females, there is no epidemiologic or statistical information on ACD among pregnant females.1 They recommended therapies used in atopic dermatitis (AD) to also be used in ACD given that both have similar treatment options in the general population with mild potency topical corticosteroids as first-line treatment.1 There is currently very little literature on patch testing and ACD in pregnancy, thus limiting our discussion. To bridge the current knowledge gaps, we present this summary as a call to action for data collection under the guidance of the European Society of Contact Dermatitis. Establishing a data registry where clinicians may submit de-identified details on pregnant patients who had undergone patch testing may be valuable shared resource (e.g., gestational age at the time of testing, test results, suspected false negatives). When and if controlled studies may be performed, comparing patch testing results during pregnancy and after can provide useful data. While a prospective study during pregnancy might be difficult for approval by the ethics committee, patch testing during the postpartum period may be considered. ACD can cause significant distress and morbidity, which necessitates a need for greater amounts of data to shape future guidelines to better care for expectant mothers. Sharon Pan: Writing – original draft; methodology; investigation; writing – review and editing; conceptualization; formal analysis. Howard Maibach: Conceptualization; supervision; writing – review and editing; methodology; investigation; writing – original draft; formal analysis. The authors declare no conflicts of interest.