Thank you for your inquiry.
The testing/provocative dosing studies with local anesthetics are traditionally performed as a means of ruling out the remote possibility that a patient would have a systemic reaction (anaphylaxis) to a local anesthetic. However, occasionally during the course of this testing, local reactions do occur, and in some instances can be due to delayed hypersensitivity to the agent in question (see abstracts copied below).
Based on the fact that your patient did not have delayed reactions to the skin tests themselves, rather only to the one mL injection, it is unlikely that a true delayed hypersensitivity reaction occurred. However, one cannot completely, with confidence, rule out this possibility.
If you feel uncomfortable about administering lidocaine to this patient with the caveat and explanation that she may have a local reaction (not a systemic reaction), then you could proceed using a similar protocol as described in the articles abstracted below. One simple way to proceed would be to choose a couple of other amide local anesthetics (e.g., mepivacaine, bupivacaine, articaine, prilocaine, et cetera) and simply inject 1 cc subcutaneously of each. If no local reaction occurred to one of these, you would have come as close as possible to assuring that she would have no reaction during the injection of that local anesthetic for the procedure.
I would not inject more than 2 of these at the same day. The injections would of course be given subcutaneously.
Thank you again for your inquiry and we hope this response is helpful to you.
Arch Dermatol. 2003 Mar;139(3):343-6.
Delayed-type hypersensitivity to lidocaine.
Mackley CL, Marks JG Jr, Anderson BE.
Department of Dermatology, Penn State Milton S. Hershey Medical Center, Hershey, PA, USA.
Background: Lidocaine hydrochloride is the preferred anesthetic agent used in outpatient surgical procedures. While type I hypersensitivity reactions to lidocaine are uncommon, type IV hypersensitivity is reported even less frequently.
Observations: Between January 1, 2001, and December 31, 2001, 183 patients were patch tested at the Penn State Milton S. Hershey Medical Center (Hershey, Pa) to the North American Contact Dermatitis Group tray. All patients who had a positive patch test reaction to lidocaine were challenged with 0.1 mL of preservative-free 1% lidocaine intradermally. Of the 183 patients patch tested, 4 had positive reactions to lidocaine, 2 of whom had histories of sensitivity to local injections of lidocaine manifested by dermatitis.
Conclusions: Delayed-type hypersensitivity to lidocaine may occur more frequently than previously thought. In cases of suspected lidocaine contact type IV sensitivity, patients should be patch tested to lidocaine. Positive patch test reactions should be confirmed by intradermal challenge with lidocaine. To provide the patient with alternative local anesthetics, patch testing should be performed with other injectable anesthetics. If positive patch test results occur, intradermal testing should follow.
Dermatitis. 2007 Dec;18(4):215-20.
Contact allergy to lidocaine: a report of sixteen cases.
Amado A, Sood A, Taylor JS.
Department of Dermatology, The Cleveland Clinic Foundation, Cleveland, OH, USA.
Lidocaine is used widely as an injectable local anesthetic, occasionally as an intravenous drug for cardiac arrhythmias, and increasingly as a topical anesthetic. Reports of allergic contact dermatitis and delayed hypersensitivity reactions to this "amide" anesthetic are limited. We report 16 cases of lidocaine contact allergy seen over 5 years. Concomitant patch-test reactions occurred with neomycin 20% (10 cases), bacitracin 20% (9 cases), fragrance mix 8% (3 cases), balsam of Peru 25% (2 cases), and dibucaine 2.5% and benzocaine 5% (1 case each). Patch tests with lidocaine dilutions (in petrolatum) gave the following results: 10% (3 of 4 positive reactions), 5% (4 of 6 positive reactions), and 1% (3 of 6 positive reactions). Intradermal testing with lidocaine 1%, mepivacaine 2%, and bupivacaine 0.5% was performed on 8 patients, resulting in positive reactions to lidocaine in 3 patients and to mepivacaine in 1 patient. Bupivacaine yielded negative results in each of the 8 patients. Relevance of delayed reactions to injectable lidocaine was definite in 2 cases; past, probable, and unknown in 1 case each; and possible in 11 cases. Delayed hypersensitivity to lidocaine may present as "suture allergy," treatment failure, typical contact allergy, or other local skin or dental reactions. Allergen substitution is based on further patch and intradermal testing, the results of which may be discordant.
Contact Dermatitis. 1996 Jun;34(6):387-9.
Delayed-type hypersensitivity to subcutaneous lidocaine with tolerance to articaine: confirmation by in vivo and in vitro tests.
Bircher AJ, Messmer SL, Surber C, Rufli T.
Department of Dermatology, University Hospital, Basel, Switzerland.
A 43-year-old woman suffered from recurrent localized swellings and an eczematous dermatitis starting 1 day after an injection of lidocaine. Intradermal patch and lymphocyte transformation tests revealed sensitization to lidocaine and cross-reactivity to the other aminoacylamide local anesthetics bupivacaine, mepivacaine and prilocaine, but not to articane. Contact allergy to the ester local anesthetics benzocaine, procaine and tetracaine, the quinoline or aminoacylamide cinchocaine, and the preservatives methylparaben and metabisulfite, was excluded. A subcutaneous challenge with articaine was well tolerated.
Contact Dermatitis. 1998 Nov;39(5):265-6.
Allergic contact dermatitis from lignocaine: report of 29 cases and review of the literature.
Weightman W, Turner T.
East Adelaide Medical Centre, South Australia, Australia.
Phil Lieberman, M.D.