Contact dermatitis caused by pharmaceutical ointments containing 'ozonated' olive oil.

Olive oil is a mixture of several glycerides of (mainly) oleic acid, but also palmitic, linoleic, stearic and arachidic acids, and also contains squalene, phytosterol, tocopherol and phenolic compounds. It is considered to be a weak irritant and a low-risk sensitizer (1), with the actual allergen(s) being unknown. Apart from its culinary use and its presence in cosmetics, itmayalso beused in topical pharmaceutical products (including compounded formulations). It is also occasionally used as a vehicle for patch testing. We report 2 patients with contact dermatitis caused by topical pharmaceuticals containing so-called ‘ozonated’ olive oil, that is, olive oil enriched with ozone (O3). Such oil may be partially or fully ozonated, with the former being more liquid and having a green-yellowish colour (more closely resembling plain olive oil), and the latter beingwhite to colourless and having greater viscosity (2).