Experimental elicitation with hydroxyisohexyl‐3‐cyclohexene carboxaldehyde‐containing deodorants

Abstract

Hydroxyisohexyl-3-cyclohexene carboxaldehyde (HICC) known as Lyral is a frequent allergen. It is used in more than 50% of marketed deodorants. The aim of the present study was to determine elicitation thresholds for HICC under simulated conditions of deodorant use. 15 patients with previously diagnosed contact allergy to HICC were patch tested with 5 solutions of HICC-scented and HICC-unscented deodorants. Patients and 10 healthy controls performed a use test in the axillae using deodorants scented with HICC in increasing concentrations and unscented deodorants as control. The concentration of HICC was increased every second week (200, 600, and 1800 p.p.m.) until either a reaction developed or for 6 weeks. 14 patients completed the study, and all developed unilateral eczema from the HICC-containing deodorant, while controls were all negative (P= 0.004). In 9/14 patients, a positive use test developed during the first 2 weeks to the deodorant containing 200 p.p.m. HICC. Positive correlations were found between the day of positive use and patch test threshold concentration of the HICC solutions (r= 0.71, P= 0.01) as well as the patch test thresholds of the HICC-scented deodorants (r= 0.74, P= 0.007). In conclusion, HICC elicits allergic contact dermatitis in a high proportion of sensitized individuals at common usage concentrations in deodorants.

Hydroxyisohexyl 3-cyclohexene carboxaldehyde allergy: relationship between patch test and repeated open application test thresholds

“…In the patch test the ED 10 was 0·66 μg HICC cm −2 . This correlates well with the results from two other HICC studies where the ED 10 was 0·85 μg HICC cm −2 , 13 and 1·17 μg HICC cm −2 , 14 respectively. The ED 10 in our study is slightly lower than the ED 10 from these two studies, which might be because two of the test subjects were very reactive, one of those had a beginning flare of eczema, so they probably represent one end of the elicitation spectrum.…”

“…Many deodorants contain fragrances; and the exposure when using a deodorant must be considered as semi‐occluded; therefore the evaporation is limited. In a repeated deodorant exposure study 14 100% of allergic persons had a positive reaction to a median dose per application of 0·79 μg HICC cm −2 , whereas in our study only 75% reacted to a ROAT dose of 3·57 μg HICC cm −2 . Furthermore, patients with fragrance allergy report deodorant sprays to be the most frequent cause of the first time rash, 51 so evidence speaks for evaporation as an important factor when looking at fragrance allergy.…”

“…If this is true in vivo , the actual accumulated dose over time in the open test is much lower than the dose calculated by adding up the dose applied everyday. An in vitro study 49 using radiolabelled HICC has shown that only 13·8% of radioactivity associated with a single dose of 14 C‐HICC evaporated from a skin sample during 24 h compared with 9·5% in the occluded test, a much lower value than estimated in our study. A study investigating the concentration stability of fragrance test preparations applied in test chambers stored at room temperature has shown that the fragrance allergen concentration decreases rapidly, indicating a high evaporation rate at room temperature 50 .…”

“…But because a considerable number of individuals are already sensitized, and some might not be diagnosed, and those who are diagnosed have difficulties in reading the labelling and identifying the allergens to which they are allergic, 11,12 a maximum limit should also prevent elicitation. Exposure studies showed that among sensitized patients 11 of 18 (61%) reacted to a repeated open application test (ROAT) of 0·5% HICC 13 and nine of 14 (64%) reacted to a repeated deodorant exposure of 0·02% HICC, 14 so more than half of sensitized individuals are not protected by the current recommendations. Such data call for a more systematic risk assessment of allergens, according to the real‐life exposure.…”

Contact allergens for armpits—Allergenic fragrances specified on deodorants

“…Ingredients of deodorant sprays can enter the human body also via inhalation. The quantitative exposures are relevant as there is a dose response relationship in persons sensitive to a certain fragrance Jorgensen et al, 2007;Svedman et al, 2003).…”