Fragrance Skin Sensitization Evaluation and Human Testing: 30-Year Experience

Area of Science:

• Dermatology
• Toxicology
• Cosmetic Science

Background:

• The human repeated insult patch test (HRIPT) is a long-standing method in the fragrance industry for safety assessment.
• Its primary application is to verify the absence of skin sensitization potential at a specific dosage.

Purpose of the Study:

• To compile and analyze data from over three decades of HRIPT studies.
• To document the accumulated experience and outcomes of HRIPT in evaluating skin sensitization.

Main Methods:

• A retrospective analysis of HRIPT studies adhering to a standardized protocol.
• Inclusion criteria required a minimum of 100 participants per study.
• Data was collected from 154 studies involving 134 different substances and 16,512 volunteers.

Main Results:

• The majority of studies confirmed no induction of sensitization at the tested doses.
• Overall, allergy was induced in 0.12% of subjects (20 out of 16,512).
• In the last 11 years, only 3 out of 9,854 subjects (0.03%) showed sensitization, indicating a declining trend.

Conclusions:

• The HRIPT demonstrates that de novo sensitization induction is infrequent and becoming rarer.
• Improvements in defining safe HRIPT doses, informed by other sensitization assays, and stricter protocol adherence contribute to this trend.
• HRIPT remains crucial, highlighting that non-human toxicological predictions can be imperfect.