Contact sensitivity to emulsifiers.

Common emulsifiers were tested in over 1,200 patients with eczema. Triethanolamine stearate tested at 5% in petrolatum caused irritant reactions in 9.5% of the patients. On the other hand, non-ionic emulsifying agents tested at 10-20% produced irritation in only a few cases. Allergic reactions were found in 2.1% of those tested. Lanette, sorbitan sesquioleate, the Spans, polyoxyethylene oxypropylene stearate, polyoxyethylene sorbitol lanolin derivative, and triethanolamine stearate each elicited allergic reactions in 0.3-0.7% of the cases. The Tweens caused an allergy in only two cases, but glycerol monostearate caused no reaction at all. Five out of six patients sensitive to sorbitan sesquioleate reacted positively to the Spans as well. The patients allergic to one or more emulsifiers were also sensitive to several other substances included in our routine test series with the exception of four patients who reacted only to the emulsifying agents.