Editing Local anesthetic (section)

==== Immunologic allergy ====

Adverse reactions to local anesthetics (especially the esters) are not uncommon, but legitimate [[allergy|allergies]] are very rare. Allergic reactions to the esters is usually due to a sensitivity to their metabolite, [[para-aminobenzoic acid]], and does not result in cross-allergy to amides.<ref name="Dolan, R. 2004">{{cite book | vauthors = Dolan R |title=Facial plastic, reconstructive, and trauma surgery |publisher=Marcel Dekker |isbn=978-0-8247-4595-0|date=2003-10-17 }}</ref><ref name="ReferenceA">Univ. of Wisconsin, Local Anesthesia and Regional Anesthetics</ref> Therefore, amides can be used as alternatives in those patients. Nonallergic reactions may resemble allergy in their manifestations. In some cases, skin tests and provocative challenge may be necessary to establish a diagnosis of allergy. Also cases of allergy to [[paraben]] derivatives occur, which are often added as preservatives to local anesthetic solutions.