An itchy red rash around the mouth and hypersensitive lips can be an indication of an allergy to flavouring agents in foods.
An even more common symptom is an itchy rash on the palms for instance, or the whole body, says Anne Hundgeburth of the Association of German Dermatologists.
Often these reactions are caused by flavourings such as cinnamon or vanilla, widely used in Christmas treats.
Cinnamic acid and vanillin are contained in Balsam of Peru, which is used in the food and beverage industry as well as for naturopathic and pharmaceutical drug preparations. If a dermatologist determines an allergy to the balsam, the patient will have to avoid a great deal of foods and drinks.
This would include spices such as cinnamon, vanilla, citrus rind, cloves and nutmeg.
Flavoured teas, tobacco, commercially-baked products or chocolate and nougat, and hot spiced wine would also become taboo. The same applies to a range of soft drinks, liqueurs, cocktails and ice cream.