Allergenicity and cross-reactivity of coconut oil derivatives: A double-blind randomized controlled pilot study.
BACKGROUND
Counseling of patients with cocamidopropyl betaine (CAPB) allergy is difficult because the cross-reactivity of CAPB with other coconut-derived surfactants, coconut oil, and coconut fatty acids is largely unknown.


OBJECTIVE
To provide pilot data regarding the cross-reactivity and allergenicity of surfactants derived from coconut oil.


METHODS
A randomized double-blind controlled pilot study of 10 control patients and 12 patients previously found to be allergic to CAPB. Eleven coconut-derived surfactants, as well as coconut oil and lauric acid, were applied in random order according to standardized patch-test procedures with readings at 48 and 92 hours. The primary outcome measure was the frequency of positive patch-test reactions to each allergen.


RESULTS
Only 3 of the 12 patients with previous reactions to CAPB reacted on retesting, and all of these reactions were doubtful. Fifty-nine percent of the study patients had reactions to triethanolamine polyethylene glycol-3 (TEA-PEG-3) cocamide sulfate as compared to none of the controls (p = .005).


CONCLUSIONS
Reactions to CAPB were only 25% reproducible. These results substantiate previous experience that doubtful and mild reactions to CAPB may represent irritant reactions as opposed to true allergic reactions. TEA-PEG-3 cocamide sulfate was the only agent that had a statistically significant higher rate of reactions in the study group as compared to the control group.
Shaffer
Kristina K
KK
Department of Dermatology, School of Medicine, University of Minnesota, MN, USA.
Jaimes
Juan P
JP
Hordinsky
Maria K
MK
Zielke
Gary R
GR
Warshaw
Erin M
EM
D000328:Adult; D000368:Aged; D000485:Allergens; D001622:Betaine / Q000009:adverse effects / Q000031:analogs & derivatives*; D000074263:Coconut Oil; D003429:Cross Reactions; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis* / Q000209:etiology; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010328:Patch Tests; D010938:Plant Oils / Q000009:adverse effects* / Q000737:chemistry; D013501:Surface-Active Agents / Q000009:adverse effects*
D000485:Allergens; D010938:Plant Oils; D013501:Surface-Active Agents; D001622:Betaine; C077055:cocamidopropyl betaine; D000074263:Coconut Oil