Table 9-2: Possible sensitisers.

Substance (INCI) name CAS number Structural alerts
Note: § Classified as R43.
Ambrettolide 7779-50-2 Possible prehapten
Amylcyclopentanone 4819-67-4 Schiff base; the combination of reactivity and hydrophobicity may be enough to confer sensitisation
Benzyl acetate 140-11-4 Prohapten via hydrolysis leading to benzyl alcohol
Carvacrol  499-75-2 Possible prehapten
Cuminaldehyde 122-03-2 Schiff base and possible prehapten
alpha-Cyclohexylidene benzeneacetonitrile 10461-98-0 Possible Michael acceptor
Cyclopentadecanone 502-72-7 Schiff base; the combination of reactivity and hydrophobicity may be enough to confer sensitisation
trans-beta-Damascone 23726-91-2 Possible Michael acceptor
trans-trans-delta-Damascone 71048-82-3 Possible Michael acceptor and possible prehapten
gamma-Damascone 35087-49-1 Possible Michael acceptor and possible prehapten
Dihydromyrcenol  18479-58-8 Possible prehapten
2,3-Dihydro-2,2,6-trimethylbenzaldehyde 116-26-7 Possible Michael acceptor and possible prehapten and possible prohapten
2,4-Dimethyl-3-cyclohexen-1-carboxaldehyde § 68039-49-6 Schiff base and possible prehapten
Dimethyltetrahydro benzaldehyde 68737-61-1 Schiff base and possible prehapten
6-Ethylideneoctahydro-5,8-methano-2H-benzo-1-pyran 93939-86-7 Possible prehapten
2-Ethyl-4-(2,2,3-trimethyl-3-cyclopenten-1-yl)-2-buten-1-ol 19-61-6 Possible prehapten
Ethyl vanillin 121-32-4 Complex
Heliotropine 120-57-0 Possible prohapten
3α,4,5,6,7,7α-Hexahydro-4,7-methano-1H-inden-5(or 6)-yl 54830-99-8 Possible prehapten
Substance (INCI) name CAS number Structural alerts
acetate
Hexahydro-methanoindenyl propionate 68912-13-0 Possible prehapten
Ionone isomeric mixture 8013-90-9 Possible Michael acceptor and possible prehapten
alpha-Ionone 127-41-3 Possible Michael acceptor and possible prehapten
beta-Ionone 79-77-6 Possible Michael acceptor
Isobergamate  68683-20-5 Possible prehapten
Isolongifoleneketone 33407-62-4 Schiff base; the combination of reactivity and hydrophobicity may be enough to confer sensitisation
Longifolene§  475-20-7 Possible prehapten
Methoxycitronellal  3613-30-7 Schiff base
Methyl decenol 81782-77-6 Possible prehapten
Methyl ionone (mixture of isomers) 1335-46-2 Possible Michael acceptor and possible prehapten
Methylionantheme 55599-63-8 Possible Michael acceptor and possible prehapten
5-Methyl-alpha-ionone 79-69-6 Possible Michael acceptor and possible prehapten
Myrtenol  515-00-4 Possible prehapten
Nopyl acetate 128-51-8 Possible prehapten
Phytol 150-86-7 Possible prehapten and/or prohapten
Rhodinol  6812-78-8 Possible prehapten
Terpineol acetate (isomer mixture) 8007-35-0 Possible prehapten
alpha-Terpinyl acetate 80-26-2 Possible prehapten
Tricyclodecenyl propionate 17511-60-3 Possible prehapten
Verdyl acetate 2500-83-6/ 5413-60-5 Possible prehapten

Source: SCCS,  Opinion on Fragrance allergens in cosmetic products, page 68-69