The value of a mixture of cassia and citronella oils for detection of hypersensitivity of essential oils.

The authors suggest the introduction of a mixture of two essential oils (citronellol and cassia) for consecutive testing of patients with dermatitis. The choice of these two oils is made on the basis of earlier investigations. Chromatographic investigation demonstrated that in this mixture no new peaks appear and no peaks disappear. In accord with this, skin tests with the mixture yielded positive results in nearly all cases of hypersensitivity to citronella or cassia oil and in these cases only. It is suggested that by using the mixture the probability of detecting hypersensitivity to essential oils is increased.