P-lactam allergy

S. aureus MSSA Antistaphylococcal penicillin P-Lactam allergy ... 

Discuss the importance of P-lactam allergy screening and how this could impact resistance and health care costs. 

P-Lactam allergy Refers to patients who experience allergic reactions to the P-lactam class of antimicrobials. 

Adverse effects include reactions at the site of infusion, rashes, gastrointestinal upset, hepatitis, thrombocytopenia and neutropenia. It appears to have a remarkably low risk of causing p-lactam allergy, and may be used with caution in some penicillin-allergic patients. 

Although claimed to be a useful test in the hands of some experienced with the technique, others have found it unreliable and difficult to standardize. Yet to be validated and stiU essentially a research tool, the test is claimed to have a sensitivity of 74 % with a rather low specificity of 85 %. One group found an overall sensitivity of 62 % and a specificity of 92.8 % in 51 patients with a well-documented history of p-lactam allergy (31 immediate reactors and 19 non-immediate). This was made up of sensitivities of 64.5 % and 57.9 % for the immediate and non-immediate groups, respectively, but the proliferative responses, expressed as stimulation indices. 

In one case of tubulointerstitial nephritis and nephrotic syndrome induced by Triazolam, a sleep inducer numerous eosinophils [85] were found to infiltrate glomeruli and interstitium suggesting that eosinophils may be pathogenic in this situation. An association with tubulointerstitial nephritis and nephrotic syndrome has also been occasionally reported for penicillin/ amoxicillin induced nephropathies [86]. Several reports have analyzed T-cells in penicillin-induced allergy. CD4 T-cells specific for penicillin may be derived from the patients and produce mainly lL-5, some of them being perforin positive with a cytolytic potential [87]. 2) P-lactam specific clones may be obtained only from patients with adverse reactions the clones were Th2 whatever the type of clinical manifestations and... 

Drug Allergy Induced ADRs with P-lactams... 

To investigate the role of these cytokines in immediate skin reactions in humans, single nucleotide polymorphism (SNP) studies were conducted within small subsets of patients known to have allergies to p-lactams (Guglielmi et al. 2006a Qiao et al. 2007 Yang et al. 2005). SNPs within the IL-4, IL-13, IFN-y, and their respective... 

When CAST results are compared to allergen-specific serum IgE antibody results, correlations are found but they are generally not high, for example, for protein allergens involved in inhalant allergies. However, with allergy to p-lactam antibiotics, the determination of drug-specific IgE is claimed to be less sensitive than the CAST . 

Fig. 5.3 Side-by-side two- and three-dimensional penicillin structure highlighting the side chain (R), p-lactam, and thiazolide ring structures. From Baldo BA. Diagnosis of allergy to penicillins and cephalosporins. Allergy Clin Immunol Int. 2000 12 206. Reprinted with permission from 2000 Hogrefe Huber Publishers (now Hogrefe Publishing, http //www.hogrefe.com)...

It seems prudent to skin test all patients with a history of allergy to a penicillin if, at the time, penicillin remains the indicated drug of choice. Skin testing should be carried out immediately before administration of the drug and repeated before any subsequent courses. Skin testing with penicillins or any other p-lactam is absolutely contraindicated in patients with a history of Stevens-Johnson or Lyell s syndrome (toxic epidermal necrolysis), exfoliative dermatitis, or other reactions where p-lactam drug administration is contraindicated. 

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