Case reports: type I hypersensitivity to lidocaine.

Lidocaine hydrochloride is the most commonly used anesthetic agent in dermatology. Despite its widespread and frequent use, adverse reactions to lidocaine are uncommon. The majority of side effects include vasovagal reactions and local side effects consisting of bruising and edema at the injection site. Immunologically mediated allergic reactions are thought to account for only 1% of these adverse reactions. We report an extremely rare case of a true type I hypersensitivity allergy to lidocaine hydrochloride.