Simultaneous [correction of Spontaneous] allergy to ampicillin and local anesthetics

Hypersensitivity to local anaesthetics--update and proposal of evaluation algorithm

Local anaesthetics (LA) are widely used drugs. Adverse reactions are rare but may be caused by delayed-type hypersensitivity reactions and probably also immediate-type reactions. As it is not always easy to clinically differ between these subtypes, allergy skin testing should be considered. Although numerous test protocols have been published, how patients with hypersensitivity reactions to LA are ideally evaluated remains a topic of discussion. This review attempts to generate a comprehensive update on allergic reactions to LA and to present an algorithm that can be used for the evaluation of patients suspected with immediate- and delayed-type immune reactions. Literature was examined using PubMed-Medline, EMBASE, Biosis and Science Citation Index. Based on the literature, the proposed algorithm may safely and rapidly distinguish between immediate-type and delayed-type allergic immune reactions.

Evaluation of adverse reactions to local anesthetics: experience with 236 patients

BACKGROUND

Adverse reactions to local anesthetics (LAs) are frequently reported. Although most of these reactions are not immune mediated, many patients are referred to allergy clinics and undergo extensive evaluation.

OBJECTIVE

To determine the prevalence of true LA allergy among the patients referred for suspected hypersensitivity and to evaluate the usefulness of the currently used evaluation protocol.

METHODS

A total of 236 patients referred to our allergy clinic for investigation of LA hypersensitivity were included in this study. The evaluation protocol was composed of skin prick and intradermal tests, followed by subcutaneous challenge with unrelated LA preparations that contained preservatives.

RESULTS

Skin prick and intradermal test results were negative for all subjects. No objective adverse reactions were observed during the challenge in all but 1 patient, who developed local erythema at the site of injection and later underwent an uneventful challenge with a different LA.

CONCLUSIONS

Allergic reactions were not reproduced during testing and challenge with LA preparations that contained preservatives or preservatives with adrenaline in our large group of patients with suspected LA allergy. Since both prick and intradermal skin test results were negative in all the patients and did not provide us with useful information, we propose to modify the standard protocol by omitting intradermal tests and shortening the challenge. We also suggest that the whole procedure be performed with LAs that contain preservatives, which are usually the preferred preparations widely used in daily practice.

Distinct delayed T-cell response to beta-methasone and penicillin-G in the same patient

BACKGROUND

Multiple drug allergy syndrome is a clinical condition characterized by reactions against more than one different class of, both pharmacologically and structurally, unrelated drugs. Scanty data are available to date about a multiple drug delayed hypersensitivity syndrome. Our aim was to report the case of a delayed reaction to both beta-methasone (beta-MT) and penicillin-G (pen-G) occurring in the same patient, and analyse beta-MT- and pen-G-specific T-cell Lines (TCLs) with regard to their specificity, phenotype and cytokine profile.

METHODS

We generated two drug-specific TCLs from biopsies at the site of positive intradermal reactions, and analysed their immunophenotype, T-cell receptor Vbeta (TCR-Vbeta) domains expression and cytokine profile.

RESULTS

We demonstrated the specificity of the T cells isolated from positive intradermal test reactions to pen-G and beta-MT through the strict dose-dependent proliferation in response to drug-pulsed autologous antigen presenting cells. Fluorescence activated cell sorter (FACS) analysis revealed a predominance of CD4+ cells in the inflammatory cell infiltrate of intradermal test with beta-MT, while a predominance of CD8+ T cells in the site of delayed reaction to pen-G was found. The drug specific CD4+ and CD8+ T cells were heterogeneous, with regard to TCR-Vbeta usage. CD8+ pen-G-TCL displayed a preferential T helper 2 (Th2) profile, while a substantially heterogeneous pattern of cytokine production characterized specific beta-MT TCL.

CONCLUSION

The study describes the coexistence in the same patient of a delayed hypersensitivity to both penicillin G and beta-MT, driven, respectively, by pen-G-specificTh2-skewed CD8+ and beta-MT specificTh0 CD4+ T cells. This case further support the existence of a multiple drug allergy syndrome also for delayed hypersensitivity.

Allergy to local anaesthetics in dentistry. Myth or reality?

BACKGROUND

Local anesthetics (LA) are frequently used in dentistry. Although these drugs are usually well-tolerated, they can sometimes provoke adverse reactions of various types and severity. The true incidence of LA allergic reactions is unknown. The objectives of this study were (i) to evaluate the incidence of immediate adverse events in subjects requiring local anesthetic injection in order to receive dental treatment; (ii) to assess the incidence of anaphylactic allergic reactions among those recorded as adverse events and (iii) to analyze the relationship between the atopic antecedents of these patients and documented allergic reactions.

MATERIALS AND METHODS

A prospective, open-label, non-comparative study including 5,018 subjects who received LA during dental treatment, despite their age, was carried out in 7 private or public odontological centers. All the possible reactions that could appear during the first hour of anesthetic administration were assessed.

RESULTS

Twenty-five adverse reactions were diagnosed, representing 0.5 % of the study population. None of these reactions was due to an allergic cause. Most (22/25) were mild, quickly reversible psychogenic or vasovagal reactions. One case was related to defects in the anesthetic technique. In two further cases, allergic etiology was ruled out after skin and dose provocative challenge tests with the anesthetic. In conclusion, allergic reactions to LA are very rare. Most adverse reactions are psychogenic or vasovagal. Physicians and dentists should be aware of these facts in order to minimize the frequent fears and myths concerning the use of LA in the dentist's office.