Eucalyptus oil and tea tree oil.

Dear Sir, We read the excellent short review article of Higgins et al. (1) on contact allergy to and the safety of eucalyptus oil with great interest. Having recently finished writing a full literature review of contact allergy to and the chemical composition of essential oils (2), we would like to give some additional information on eucalyptus oil. Also, we will address the question raised by these authors of why there is a low rate of allergic contact dermatitis caused by eucalyptus oils, but there are multiple reports of allergic contact dermatitis caused by tea tree oil, although this oil has constituents in common with eucalyptus oil (1).