ABSTRACT
Insufficient knowledge of the chemical composition of essential oils and difficulties in ascertaining whether oils or their ingredients are present in materials with which the patients have contact may partly be responsible. Undiluted oils are also frequently applied for therapeutic purposes, notably tea tree oil. Dermatitis will appear at the site of application and may stay limited to the primary site, but spreading of dermatitis is not infrequent and even generalization occurs occasionally. Unilateral dermatitis of the cheeks may be caused by lavender drops applied on the pillow for their presumed hypnotic effects. Essential oils are frequently added to toothpastes, especially spearmint, peppermint and cinnamon oils. Contact allergy may lead to symptoms of the oral mucosa, the lips and the perioral skin. In Japan, in the 1960s and 1970s, many female Japanese patients developed facial pigmentation following dermatitis of the face.
