Intradermal Tests for Diagnosis of Drug Allergy are not Affected by a Topical Anesthetic Patch

Abstract

The use of topical anesthesia to perform intradermal tests (IDTs) for drug allergy diagnosis was never investigated. We aimed to determine the effects of a topical anesthetic patch containing prilocaine-lidocaine on wheal size of IDT with drugs. Patients who had positive IDT as part of their investigation process of suspected drug hypersensitivity were selected. IDT were performed according to guidelines. Anesthetic patch (AP) was placed and the same prior positive IDT, as well as positive histamine skin prick test (SPT) and negative (saline IDT) controls, were performed in the anesthetized area. Patients with negative IDT were also included to check for false positives with AP. Increase in wheals after 20 minutes both with and without AP was recorded and compared. 45 IDT were performed (36 patients), of which 37 have been previously positive (14 antibiotics, 10 general anesthetics, 6 non-steroidal anti-inflammatory drugs, 3 iodinated contrasts, 3 anti-Hi-histamines and 1 ranitidine). Mean histamine SPT size without the AP was 4.7 mm [95%CI (4.4-5.1]), and 4.6 mm [95%CI(4.2-5.0)] with anesthesia. Mean wheal increase in IDT for drugs without the anesthesia was 4.5 mm [95%CI(3.3-5.7)] and with anesthesia was 4.3 mm [95%CI(2.8-5.8)]. No statistical significant differences were observed between skin tests with or without AP for histamine SPT (P=0.089), IDT with saline (P=0.750), and IDT with drugs (P=0.995). None of the patients with negative IDT showed positivity with the AP, or vice-versa. The use of an AP containing prilocaine-lidocaine does not interfere with IDT to diagnose drug allergy, and no false positive tests were found.

Desensitization to carboplatin in low‐grade glioma. A revision of 100 treatments in children

“…11 Validation of ST with EMLA® with other drugs found no differences in ST results but platins were not evaluated in this study. 12 Although none of the suspected HSR was confirmed by ST, the high rate of BR during RDD (60%) corroborates the initial diagnosis.…”

“…11 Validation of ST with EMLA® with other drugs found no differences in ST results but platins were not evaluated in this study. 12 F I G U R E 1 For understanding purpose, an adapted protocol was adjusted according to 2 hypothetical scenarios, based on our patients Although none of the suspected HSR was confirmed by ST, the high rate of BR during RDD (60%) corroborates the initial diagnosis.…”

Desensitization in children allergic to drugs: Indications, protocols, and limits

“…33 In young children, skin tests can be very challenging to perform, although the application of an anesthetic ointment including lidocaine and prilocaine has shown to effectively reduce discomfort associated with intradermal tests, without interfering with its results. 34 Moreover, children undergoing chemotherapy are frequently receiving treatment protocols that include steroids and other drugs that can compromise skin test results. 33 The decision to desensitize after a risk/benefit evaluation should be taken by an experienced allergist in this field, together with the specialist treating the children.…”

“…Skin tests to diagnose immediate reactions can be done but are only validated for some drugs, like beta‐lactams and platinum salts 33 . In young children, skin tests can be very challenging to perform, although the application of an anesthetic ointment including lidocaine and prilocaine has shown to effectively reduce discomfort associated with intradermal tests, without interfering with its results 34 . Moreover, children undergoing chemotherapy are frequently receiving treatment protocols that include steroids and other drugs that can compromise skin test results 33…”

The effect of topical lidocaine on intradermal testing in atopic dogs

“…An EMLA (eutectic mixture of lidocaine and prilocaine) cream or patch used before intradermal and prick testing in people significantly reduces pain without influencing wheal size. 9,10 EMLA cream also has been shown to significantly reduce pain in rabbits undergoing ear tattooing, as well as in laboratory dogs, cats and rabbits undergoing venipuncture. 11,12 Topical local anaesthetic application is safe and well-tolerated in people.…”