[4-[[4-(diethylamino)phenyl]phenylmethylene]-2,5-cyclohexadien-1-ylidene]diethylammonium acetate

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

Several studies were published and examined in a weight of evidence approach with the results from exposure of human skin.

Bielicky T. and Novak M. (1969) applied the test substance to skin of patients previously found to be reactive toward triphenylmethane. The test substance was applied in a concentration of 2 % in water. A positive reaction was detected in 11 out of 11 patients.

A case report by Shehade S.A. and Foulds I.S. (1986) described a patient that developed eczema after treatment with a gel containing the test substance. After determination of the treatment healing was observed. A following patch test revealed a positive reaction to a concentration of 0.5 and 2 % of the test substance in water on the patient’s skin.

Björnberg A. and Mobacken H. (1972) performed a single dose treatment on healthy back skin of humans. A concentration of 1 % test substance induced no alterations. In addition the forearm skin was stripped and the test substance was applied two times. Here it induced painful superficial ulcerations. Healing of the necrotic tissue occurred after 2-3 weeks leaving hyperpigmentation and scars.

Manzini et al. (1991) established with 20 healthy volunteers that the test substance (concentration of 2 % pet.) was non-irritant on skin. 569 patients that presented with a dermatitis considered to be allergic in origin were patch tested with the same concentration of the test substance. The test was performed on healthy skin on the back of the patients. Two days after application the test substance was removed and the skin area was examined the next day. A positive reaction of the skin was found in 2 out of 569 patients. 

The review from Hatch K.L. and Maibach H.I. (1995) stated that the test substance was found to belong to a group of dyes that induces allergic contact dermatitis in patients. It was found to be an allergen discovered in patients using patch tests.

Conclusion

Taken together, the studies and the case report revealed a possible development of contact dermatitis in humans after exposure to the test substance. A predisposition for reaction to substances with similar properties like the test substance seemed to be necessary for a reaction on healthy skin. The test substance was classified and labelled as skin sensitising to humans based on the above publications.

Migrated from Short description of key information:
Potential sensitisation effects of the test substance to human skin were described in several studies and one case report. Mostly patients with a suspected development of contact dermatitis were patch tested with the test substance. Patients with a known reaction to substances similar to the test substance showed a reaction. From patients with a not further investigated origin of the dermatitis only few developed a reaction after exposure to the test substance. A small study on healthy volunteers showed no reaction after application on the back skin while a reaction was observed on previously stripped skin of the forearm. Therefore the substance might be considered sensitizing in humans prone to allergic skin reactions.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The available experimental human test data are reliable and suitable for classification purposes under Regulation 1272/2008. As a result the substance needs to be classified and labelled as skin sensitising cat 1, H317 "May cause an allergic skin reaction" under Regulation (EC) No 1272/2008, as amended for the sixth time in Regulation (EC) No 605/2014.