Quantitative patch and repeated open application testing in hydroxyisohexyl 3-cyclohexene carboxaldehyde...

Area of Science:

• Dermatology
• Toxicology
• Cosmetic Science

Background:

• Hydroxyisohexyl 3-cyclohexene carboxaldehyde (HICC) is a common fragrance ingredient.
• Allergic contact dermatitis is a significant concern with fragrance compounds.
• Establishing safe concentration limits for sensitized individuals is crucial for consumer safety.

Purpose of the Study:

• To determine the maximum concentration of HICC that does not elicit an allergic reaction in patients with known sensitization.
• To provide data for setting safe usage levels of HICC in cosmetic products.

Main Methods:

• Repeated Open Application Testing (ROAT) on 64 sensitized subjects using HICC in perfume and cream formulations at varying concentrations (0.005-2.5%).
• Confirmatory patch testing with HICC preparations at 2.5% and 5% concentrations.
• Statistical analysis to correlate ROAT results with patch test sensitivity and specificity.

Main Results:

• Estimated tolerable HICC concentrations for 90% of sensitized individuals were <88.2 ppm for cream and <270 ppm for perfume.
• Patch test sensitivity ranged from 88.5-98.1%, with specificity from 37.5-87.5%.
• A significant inverse correlation was found between ROAT concentrations and patch test reaction strength, indicating varying susceptibility levels.

Conclusions:

• Recommended use concentrations to protect 90% of sensitized individuals range from 0.009% to 0.027%, varying by product type.
• Avoiding excessive HICC concentrations is essential to prevent further sensitization.
• Continuous monitoring is necessary to validate the effectiveness of HICC exposure recommendations.