[Contact allergy to 3-dimethylaminopropylamine and cocamidopropyl betaine]. / Alergia de contacto a 3-dimetilaminopropilamina y cocamidopropil betaína.

It has been discovered that all individuals who are allergic to cocamidopropyl betaine (CAPB) are sensitized to 3-dimethylaminopropylamine (DMAPA) and to amidoamine, molecules which are intermediaries in CAPB synthesis, and which persist as impurities in the material that is sold; the amounts vary, depending on the quality of the CAPB in the end product. We present three cases of allergic contact dermatitis to DMAPA. In all three cases, the skin tests for DMAPA were positive, while there was no reaction to CAPB. The current relevance of these tests was confirmed by the patients' re-exposure to the suspect products themselves, which contained CAPB. Contact allergy to CAPB is now infrequent, partly because of the increasing use of new non-irritating surfactants that have been introduced on the market in the last decade. However, cases of patients allergic to commercial CAPB who only react to DMAPA -and not to CAPB- when they are patch tested are still being reported. DMAPA itself, and other molecules like amidoamine, would be the true allergens, and some cases of CAPB allergy are therefore being overlooked because DMAPA is not always included in the cosmetics series. CAPB may no longer be necessary in patch tests, as DMAPA seems to be the principal allergenic fraction in this surfactant, and also because manufacturers of skin allergens currently prepare CAPB extracts that are so pure that they are no longer a good screening tool for contact allergy to commercial CAPB.

Alergia de contacto a 3-dimetilaminopopilamina y cocamidopropil betaína / Contact allergy to 3-dimethylaminopropylamine and cocamidopropyl betaine

Se ha descubierto que todos los individuos con alergia a la cocamidopropil betaína (CAPB) se encuentran sensibilizados a la 3-dimetilaminopropilamina (DMAPA) y a la amidoamina, moléculas que son intermediarias en la síntesis de CAPB, y que persisten como impurezas en el material comercializado, en cantidades variables dependiendo de la calidad de la CAPB en el producto final. Se presentan 3 casos de dermatitis de contacto alérgica a DMAPA. En los tres las pruebas epicutáneas para DMAPA fueron positivas, mientras que no hubo reacción a la CAPB. La relevancia actual de estas pruebas fue confirmada por la reexposición de los pacientes a los productos propios sospechados, que contenían CAPB. La alergia de contacto a la CAPB es ahora poco frecuente, en parte por el creciente uso de nuevos agentes tensoactivos no irritantes introducidos en el mercado en la última década. Sin embargo, siguen dándose a conocer casos de pacientes alérgicos a la CAPB comercial que sólo reaccionan a la DMAPA ­y no a la CAPB­ cuando son parcheados. La propia DMAPA u otras moléculas como la amidoamina serían los alérgenos verdaderos y, por tanto, algunos casos de alergia a la CAPB se estarían pasando por alto debido a que la DMAPA no siempre está incluida en la serie de cosméticos. La CAPB podría no ser ya necesaria en las pruebas del parche, puesto que la DMAPA parece ser la principal fracción alergénica en este agente tensoactivo, y también porque los fabricantes de alérgenos epicutáneos elaboran unos extractos de CAPB tan puros que no son ya una buena herramienta de cribado de la alergia de contacto a la CAPB comercial

It has been discovered that all individuals who are allergic to cocamidopropyl betaine (CAPB) are sensitized to 3-dimethylaminopropylamine (DMAPA) and to amidoamine, molecules which are intermediaries in CAPB synthesis, and which persist as impurities in the material that is sold; the amounts vary, depending on the quality of the CAPB in the end product. We present three cases of allergic contact dermatitis to DMAPA. In all three cases, the skin tests for DMAPA were positive, while there was no reaction to CAPB. The current relevance of these tests was confirmed by the patients' re-exposure to the suspect products themselves, which contained CAPB. Contact allergy to CAPB is now infrequent, partly because of the increasing use of new non-irritating surfactants that have been introduced on the market in the last decade. However, cases of patients allergic to commercial CAPB who only react to DMAPA ­and not to CAPB­ when they are patch tested are still being reported. DMAPA itself, and other molecules like amidoamine, would be the true allergens, and some cases of CAPB allergy are therefore being overlooked because DMAPA is not always included in the cosmetics series. CAPB may no longer be necessary in patch tests, as DMAPA seems to be the principal allergenic fraction in this surfactant, and also because manufacturers of skin allergens currently prepare CAPB extracts that are so pure that they are no longer a good screening tool for contact allergy to commercial CAPB