The role of the skin irritation response in polysensitization to fragrances.

BACKGROUND: Contact allergy to fragrance chemicals is an increasing problem. Polysensitization is likely to be a phenotype of increased susceptibility to contact allergy. The factors that play a role in polysensitization are largely unknown. Identifying these risk factors is important with regard to future studies on the aetiology of contact allergy. OBJECTIVES: To investigate whether enhanced skin irritability is a risk factor for the development of polysensitization to fragrance chemicals. METHODS: One hundred participants characterized by fragrance contact allergy were included in our study. The participants were patch tested on the back with 25 individual fragrance chemicals and fragrance mixes I and II, and on the upper arm with sodium lauryl sulfate (SLS) (consisting of SLS concentrations of 0.45%, 0.67%, 1%, and 1.5%). Reading of both tests was performed during the following visits at days 2, 3, and 7. The response to SLS was monitored by measuring transepidermal water loss (TEWL). Polysensitization was defined as three or more allergic reactions to non-cross-reacting fragrance chemical allergens. RESULTS: Individuals with polysensitization showed significantly higher irritation responses to SLS 1% and 1.5% as assessed by TEWL. CONCLUSIONS: We found an enhanced skin irritation response to be a risk factor for the development of polysensitization to fragrance chemicals.

Do 'cinnamon-sensitive' patients react to cinnamate UV filters?

BACKGROUND: Use of sunscreens has increased dramatically worldwide, and some sunscreen chemicals may be allergens. Ultraviolet (UV) filters are added to various cosmetic products. Cinnamate UV filters are structurally related to cinnamon-related fragrances. OBJECTIVE: The purpose of this study was to determine if 'cinnamon-sensitive' patients show positive photopatch tests to cinnamate UV filters and, therefore, should avoid these UV filters. METHOD: We photopatch tested cinnamon-sensitive patients (n = 18) with cinnamon, cinnamon-related fragrances, Myroxylon pereirae, and two cinnamate UV filters. RESULTS: No positive photopatch test to cinnamate UV filters was found (95% confidence interval 0-13%). DISCUSSION: The risk of developing unwanted allergic contact dermatitis because of cinnamate UV filters in cinnamon-sensitive patients seems to be low, but our study population was small. Therefore, we recommend cinnamon-sensitive patients to perform a use test, for example the repeated open application test, before using cosmetic products containing cinnamate UV filters. In addition, physicians and patients should be aware that many sunscreens contain (cinnamon-related) fragrances and could, therefore, elicit allergic contact dermatitis in cinnamon-sensitive patients, independently from other potential sensitizing components of the sunscreen.