Gillian C. de Gannes

Atopy Associated With Positive Patch Test and Possible Allergic Contact Dermatitis

Background: Atopy is a genetic predisposition to the development of allergic reactions and the increased production of immunoglobulin E (IgE) upon exposure to environmental antigens. Clinical manifestations of atopy include asthma, atopic dermatitis (AD), and allergic rhinoconjunctivitis (ARC). Objective: To determine if cutaneous delayed hypersensitivity reactions (CDHRs) as assessed by patch testing are higher among patients with a history of atopy and with a familial predisposition to atopy. Methods: For this study, we reviewed the patch test database of the UBC Contact Dermatitis Clinic over a 4-year time span. A personal history of asthma, AD, and ARC was recorded. In addition, a family history was obtained and manifestations of atopy in family members were noted. Results: A total of 1515 patients were included in this study. Our data show that the odds ratio (OR) of a positive patch test with a personal history of atopy was 1.39, while the OR of a positive patch test with a family history of atopy was 1.69. Conversely, a personal history of respiratory atopy did not significantly affect the probability of a positive patch test, with an OR of 1.03. Conclusion: We conclude from our study that patients with a personal or family history of atopy have an increased risk of allergic contact dermatitis (ACD). These results provide further evidence for the link between atopy and ACD and suggest that children of atopic parents should avoid potential contact allergens and would likely benefit from prophylactic emollient use.

Methylisothiazolinone Contact Allergy Prevalence in Western Canada: Increased Detection With 2000 ppm Patch Test Allergen

Background: Contact allergy to methylisothiazolinone (MI) or to the combination of methylchloroisothiazolinone and MI (MCI/MI) is an important and increasing cause of allergic contact dermatitis, with prevalence rates higher than 10% in some centers. Objectives: The objective of this retrospective chart review is to provide a western Canadian perspective on whether the positive patch testing rate to MCI/MI or MI increased during the testing period of 2008 to 2015 and whether the addition of MI at 2000 ppm resulted in increased detection. Methods: We conducted a retrospective chart review of patients who tested positive (n = 104) of 2177 total patients who were patch tested for MCI/MI or MI at a community dermatology clinic in Vancouver, British Columbia, Canada, from January 2008 through April 2015. Results: One hundred and four patients had positive patch testing results for MCI/MI, MI, or both. Positive results increased over the study period, with the highest prevalence in 2015 at 9.41% for MCI/MI, 12.94% for MI, and 15.29% for either. When testing for MI at 2000 ppm was introduced in 2013, the initial positive patch testing prevalence was 6.6%, followed by 10.1% in 2014, and 12.9% in 2015. Conclusions: We demonstrate an increasing prevalence of MCI/MI and MI allergy between 2008 and 2015, with the highest prevalence of 15.29% in 2015 for MCI/MI and/or MI allergy. The addition of MI 2000 ppm greatly increased the positive patch testing yield for MI. Our results support the importance of continued efforts to monitor and regulate these preservatives.

Analysis of the prevalence of allergic contact dermatitis to sunscreen: a cohort study.

Background: As the use of sunscreens becomes more prevalent, reports of adverse effects to sunscreens have increased. Objective: To analyze a patch test database for the prevalence of allergic contact dermatitis (ACD) to sunscreen. Methods: The database was searched for positive patch test reactions to benzophenone-3. Charts were also reviewed for those who were further tested to the sunscreen series. Results: Twenty-three of the 1,527 patients seen were tested to the sunscreen series. Of these, only 4 patients had a positive reaction to a sunscreen chemical or to the product they were using. In addition, 8 of the 1,527 patients who had no specific history of sunscreen allergy reacted to benzophenone-3. Conclusion: ACD to sunscreen was found to be very uncommon (0.8%). Other final diagnoses included ACD to excipients such as fragrances or preservatives and suspected photosensitive disorders.

Decreasing Rates of Neomycin Sensitization in Western Canada.

Background: Neomycin contact sensitization rates in North America range from 7% to 13%, whereas in Europe they average approximately 1.9%. Objectives: Given that topical neomycin products are no longer readily available in Canada, the aim of this study was to examine what influence this may have had on neomycin sensitization rates in the 3 western provinces. Methods: On the basis of an observation originally communicated by L. M. Parsons and C. Zhang of the University of Calgary, which suggested significantly reduced rates of neomycin sensitization in Calgary, Alberta, Canada, a multicenter study of patch test results from 5690 patient charts was undertaken. Data from 3 other western Canadian Universities (the University of Saskatchewan, the University of Alberta, and the University of British Colombia) were analyzed. Data were available from 2001 to 2013 for the University of Saskatchewan (except 2006), whereas the University of Alberta and the University of British Columbia had data from 2009 to 2013. Descriptive statistics, trend analysis, and risk estimates were determined using SPSS version 20. Results: Sensitization rates for neomycin have decreased in western Canada and are now similar to those of Europe. Conclusions: This trend is likely influenced by the reduced availability of over-the-counter and prescription neomycin products in Canada.

HIV dermatology in Canada: cutaneous disease burden and demographic characteristics of a specialized urban practice.

Background: The introduction of antiretroviral therapies has changed the pattern of cutaneous disease in individuals infected with human immunodeficiency virus (HIV). Objective: To assess demographic characteristics, severity of immunosuppression, and frequency of dermatologic disorders in patients presenting to a Canadian specialized HIV dermatology practice. Methods: A cross-sectional study was performed of 183 consecutive outpatient and inpatient consultations to a single HIV dermatology practice from January 2007 to December 2008. Results: One hundred sixty-three (88%) patients were male, with an average age of 45. Forty-six patients were not on antiretroviral therapy. Verruca was the most common diagnosis, seen in 29 patients, followed by dermatophyte infection, seen in 27. Patients with a low CD4 count (p = .0001) and a high viral load (p = .0043) were more likely to present with an HIV-specific dermatosis. Conclusion: Cutaneous infections were the most common diagnoses in this cross section. Classic HIV dermatoses were seen more frequently in those with more advanced disease owing to HIV infection.