Contact sensitivity to lignocaine.

Lignocaine is a rare contact allergen, in contrast to other local anaesthetics such as benzocaine, which commonly sensitize. The case of a patient sensitized to lignocaine through the use of a topical medication for the treatment of haemorrhoids is reported. Previous reports show that application of a lignocaine-containing preparation for pruritus ani is the most frequent cause of sensitization to lignocaine. The significance of sensitization to lignocaine is discussed in the light of its widespread use both in local anaesthesia and as an anti-arrhythmic.