Additives are substances authorised for addition to foodstuffs or drugs to ensure proper preservation or colouring.

When a patient develops skin problems such as urticaria or milder rash-like phenomena after ingesting syrups of different composition, an allergic reaction to the additives, colouring agents or aromatisers of the syrup is probably involved.
Most “allergic” manifestations in response to local anesthetics are attributable to the additives they contain. The symptoms of itching, tachycardia and even dizziness after injection of an anesthetic may represent an allergic reaction to additives.

The adverse reactions induced by additives generally affect the skin.
In the event of such symptoms, the patient should seek the help of a specialist.