Intravenous desensitization to beta-lactam antibiotics

Sexually Transmitted Infections Treatment Guidelines, 2021

These guidelines for the treatment of persons who have or are at risk for sexually transmitted infections (STIs) were updated by CDC after consultation with professionals knowledgeable in the field of STIs who met in Atlanta, Georgia, June 11–14, 2019. The information in this report updates the 2015 guidelines. These guidelines discuss 1) updated recommendations for treatment of Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis; 2) addition of metronidazole to the recommended treatment regimen for pelvic inflammatory disease; 3) alternative treatment options for bacterial vaginosis; 4) management of Mycoplasma genitalium; 5) human papillomavirus vaccine recommendations and counseling messages; 6) expanded risk factors for syphilis testing among pregnant women; 7) one-time testing for hepatitis C infection; 8) evaluation of men who have sex with men after sexual assault; and 9) two-step testing for serologic diagnosis of genital herpes simplex virus. Physicians and other health care providers can use these guidelines to assist in prevention and treatment of STIs.

Preoperative Allergy Testing for Patients Reporting Penicillin and Cephalosporin Allergies is Cost-Effective in Preventing Infection after Total Knee and Hip Arthroplasty

BACKGROUND

Routine preoperative allergy testing in patients reporting penicillin and cephalosporin allergies increases the number able to receive cefazolin, which should reduce the risk of infection after total knee and hip arthroplasty (TKA/THA), but it remains unclear whether this practice is cost-effective. Using a break-even analysis, we calculated the cost-effectiveness of routine preoperative allergy testing for infection prevention in total joint arthroplasty patients reporting penicillin and cephalosporin allergies.

METHODS

The cost of a penicillin allergy evaluation, the cost of revision arthroplasty for prosthetic joint infection (PJI), and baseline rates of PJI in patients receiving a noncefazolin antibiotic in the perioperative period were derived from existing literature. A break-even economic model using these variables was constructed to calculate the absolute risk reduction (ARR) in infection rate needed for preoperative allergy testing to be cost-effective. The number needed to treat (NNT) was calculated from the ARR.

RESULTS

Preoperative allergy testing before TKA and THA in patients reporting penicillin and cephalosporin allergies was cost-effective if the initial infection rate decreased by an ARR of 0.810% (NNT = 123) and 0.655% (NNT = 153) for TKA and THA, respectively. Cost-effectiveness was maintained with varying allergy consultation costs, infection rates, and costs associated with PJI treatment.

CONCLUSION

Routine preoperative allergy testing and clearance are cost-effective infection prevention strategies among patients reporting penicillin and cephalosporin allergies in the setting of elective joint arthroplasty. Widespread adoption of this practice may considerably reduce the economic and societal burden associated with prosthetic infections.

Current perspective and scope of fetal therapy: part 2

Fetal therapy has been defined as any therapeutic intervention either invasive or noninvasive for correcting or treating any fetal malformation or condition. Invasive fetal therapy have its own set of maternal and fetal complications and invasive approach is not feasible in many of fetal conditions that are candidate for fetal therapy. Many such fetal conditions have been treated successfully by medical or noninvasive management. In medical fetal therapy, mothers are treated with medications which are transferred to fetus through placenta and exert positive effect on the fetus, thus avoiding complications that are seen secondary to invasive fetal therapy. The fetal conditions that have been managed with medical therapy includes fetal and neonatal alloimmune thrombocytopenia, neural tube defect, congenital adrenal hyperplasia, perinatal infections, respiratory distress syndrome, inborn error of metabolism, and congenital cystic adenomatoid malformation. This review will cover the medical or noninvasive aspect of fetal therapy and will highlight the progress made in the management of these fetal conditions.

Successful Desensitization Protocol in an Infant Following Anaphylaxis Secondary to Recombinant Factor VIIa

Background: Recombinant factor VIIa (rFVIIa) is a highly purified recombinant protein. It is approved for the treatment and prevention of bleeding episodes associated with congenital factor VII deficiency, congenital hemophilia with inhibitors, and Glanzmann's thrombasthenia. The most commonly reported adverse events are thrombolytic in nature. In this report, we present a successful desensitization protocol administered to an infant with a history of anaphylaxis to rFVIIa. Case: A male infant with a history of gingival bleeding at the age of 6 months was diagnosed with factor VII deficiency with a factor VII level of 1%. His sister also had diagnosis of factor VII deficiency. Our patient was hospitalized at 10 months of age with generalized petechiae and bloody stools. Twenty minutes after administration of rFVIIa, he developed anaphylaxis that responded to epinephrine and supportive care. Subsequently he was evaluated at the allergy clinic, where a skin prick test with rFVIIa was negative. However, the intradermal skin test, applied with 1/1,000 (1 μg/1 mL, 0.1 mL) dilution of rFVIIa, showed induration of 8 mm (positive reaction). Because there is no alternative treatment for factor VII deficiency, we developed a successful 13-step desensitization protocol with rFVIIa (NovoSeven^®). Desensitization was performed an additional 2 times using the same protocol, one of which was for a head injury and the other for a swollen knee since the period between the doses was ∼3 months. Conclusion: Allergic reactions, such as anaphylaxis can occur without prior exposure. This can be due to the high molecular weight and structural property of the biological agent. In this report, we present an effective desensitization protocol for an infant with a history of anaphylaxis to rFVIIa. Desensitization protocols in this age group should be carried out in a medical facility and with specialized staff and equipment prepared to care for anaphylaxis.

Congenital syphilis: A contemporary update on an ancient disease

Congenital syphilis (CS) rates reached a 20-year high in the United States in 2018. Unlike previous years, most babies diagnosed with CS were born to mothers who received prenatal care, indicative of the need for better provider education and guideline adherence. Current rates suggest that screening for syphilis should be performed at the first prenatal care visit and twice during the third trimester. There are two diagnostic algorithms available for use in the United States (traditional and reverse) and providers must understand how to perform each algorithm. Treatment should be administered according to stage of syphilis per Centers for Disease Control recommendations with best neonatal outcomes seen when treatment is initiated >30 days before delivery. Benzathine Penicillin G remains the only recommended treatment of syphilis during pregnancy. In viable pregnancies, a pretreatment ultrasound is recommended to identify sonographic evidence of fetal infection and treatment should be initiated with continuous fetal monitoring to evaluate for the Jarisch-Herxheimer reaction which can cause preterm labor and fetal distress. After adequate syphilotherapy, a fourfold decline in maternal nontreponemal titers may not be observed by delivery and does not correlate with rates of CS.

Heparin challenge test in patients undergoing cardiac surgery: dealing with heparin allergy

: A history of heparin hypersensitivity in patients undergoing cardiopulmonary bypass surgery poses the dilemma of which anticoagulant to use. Here, we report the successful use of a heparin challenge test in a 66-year-old female candidate for coronary artery bypass graft surgery with a past medical history of enoxaparin type I hypersensitivity after pulmonary embolism. Challenge and desensitization protocols are effectively used for essential antibiotics in patients with severe infections and/or allergies, or patients with aspirin intolerance requiring revascularization for coronary disease. A successful use of desensitization protocols to unfractionated heparin has been previously described in four patients undergoing cardiac surgery with various schemes. However, our case report indicates that a challenge test may also offer a quick, safe and effective approach in patients with a history of hypersensitivity reactions to heparin with inconclusive diagnostic tests and/or whenever the use of alternative heparins is tricky.

Protocols for drug allergy desensitization in children

Introduction: When a drug hypersensitivity reaction is proven, desensitization protocols allow the reintroduction of the molecule in patients for whom such therapy is essential. Through drug desensitization (DDS), a temporary immune tolerance is maintained for the single course of a specific therapy. In pediatrics, indications for such a procedure include children with chronic diseases, severe infectious diseases and/or malignancies, who have a proven drug hypersensitivity.Areas covered: We ran a search on PubMed and Web of Science for papers on DDS and on DDS in children. Most protocols and recommendations on DDS focus on adults and have been adapted for children. The best candidates for desensitization are children with a history of immediate, IgE-mediated drug allergy, but this therapy may be applied also in nonallergic hypersensitivities and in non-immediate reactions. Most protocols in literature focus on antibiotics, especially beta-lactams, on chemotherapeutic agents, and on monoclonal antibodies.Expert opinion: Pediatric allergists should cooperate with specialists in infectious diseases and onco-hematology to provide DDS to children in need. Standardized protocols and international guidelines are still needed to optimize such treatment and to implement it in clinical daily practice.

Loss of tolerance 5 days after discontinuing sulphonamide introduced via desensitization in delayed reaction

The fixed drug eruption is a non-immediate hypersensitivity reaction to drug, characterized by recurrent erythematous or violaceous, rounded, well-defined border plaques, which always appear in the same location every time the culprit drug is administered. The usual practice is to avoid the drug involved and to use a structurally different drug. However, there are situations in which there is no safe and effective therapy. In such situations, desensitization is the only option. We describe the case of a patient who presented fixed eruption due to sulfamethoxazole-trimethoprim, who underwent successful desensitization, but required a repeat procedure twice due to relapse after inadvertent full-dose reintroduction. In non-immediate hypersensitivity reaction to drug, the indication is controversial and there is no technical standardization. Furthermore, the time at which such tolerance is lost after discontinuing the drug involved is unknown. In severe non-immediate reactions of types II and III, desensitization is contraindicated. The patient underwent desensitisation to sulfamethoxazole-trimethoprim three times − the first with recurrence of lesions and the second and third without manifestations, all concluded successfully and with no premedication.

Antimicrobial Desensitization: A Review of Published Protocols

Antimicrobial desensitization represents a last-line option for patients with no alternative therapies, where the benefits of this intensive process must outweigh the potential harm from drug exposure. The goal of antimicrobial desensitization procedures is to establish a temporary state of tolerance to drugs that may otherwise cause hypersensitivity reactions. While no universal antimicrobial desensitization protocols exist, this review critically analyzes previously published desensitization protocols. The purpose of this review is to provide a greater insight for clinicians and institutions to ensure desensitization procedures are efficacious while minimizing potential for patient harm. With an increasing rate of antimicrobial resistance and the critical need to preserve antimicrobial agents, desensitization may represent another option in our antimicrobial stewardship toolkit.

Drug Hypersensitivity and Desensitizations: Mechanisms and New Approaches

Drug hypersensitivity reactions (HSRs) are increasing in the 21st Century with the ever expanding availability of new therapeutic agents. Patients with cancer, chronic inflammatory diseases, cystic fibrosis, or diabetes can become allergic to their first line therapy after repeated exposures or through cross reactivity with environmental allergens. Avoidance of the offending allergenic drug may impact disease management, quality of life, and life expectancy. Precision medicine provides new tools for the understanding and management of hypersensitivity reactions (HSRs), as well as a personalized treatment approach for IgE (Immunoglobuline E) and non-IgE mediated HSRs with drug desensitization (DS). DS induces a temporary hyporesponsive state by incremental escalation of sub-optimal doses of the offending drug. In vitro models have shown evidence that IgE desensitization is an antigen-specific process which blocks calcium flux, impacts antigen/IgE/FcεRI complex internalization and prevents the acute and late phase reactions as well as mast cell mediator release. Through a "bench to bedside" approach, in vitro desensitization models help elucidate the molecular pathways involved in DS, providing new insights to improved desensitization protocols for all patients. The aim of this review is to summarize up to date information on the drug HSRs, the IgE mediated mechanisms of desensitization, and their clinical applications.

Syphilis during pregnancy: a preventable threat to maternal-fetal health

Syphilis remains the most common congenital infection worldwide and has tremendous consequences for the mother and her developing fetus if left untreated. Recently, there has been an increase in the number of congenital syphilis cases in the United States. Thus, recognition and appropriate treatment of reproductive-age women must be a priority. Testing should be performed at initiation of prenatal care and twice during the third trimester in high-risk patients. There are 2 diagnostic algorithms available and physicians should be aware of which algorithm is utilized by their testing laboratory. Women testing positive for syphilis should undergo a history and physical exam as well as testing for other sexually transmitted infections, including HIV. Serofast syphilis can occur in patients with previous adequate treatment but persistent low nontreponemal titers (<1:8). Syphilis can infect the fetus in all stages of the disease regardless of trimester and can sometimes be detected with ultrasound >20 weeks. The most common findings include hepatomegaly and placentomegaly, but also elevated peak systolic velocity in the middle cerebral artery (indicative of fetal anemia), ascites, and hydrops fetalis. Pregnancies with ultrasound abnormalities are at higher risk of compromise during syphilotherapy as well as fetal treatment failure. Thus, we recommend a pretreatment ultrasound in viable pregnancies when feasible. The only recommended treatment during pregnancy is benzathine penicillin G and it should be administered according to maternal stage of infection per Centers for Disease Control and Prevention guidelines. Women with a penicillin allergy should be desensitized and then treated with penicillin appropriate for their stage of syphilis. The Jarisch-Herxheimer reaction occurs in up to 44% of gravidas and can cause contractions, fetal heart rate abnormalities, and even stillbirth in the most severely affected pregnancies. We recommend all viable pregnancies receive the first dose of benzathine penicillin G in a labor and delivery department under continuous fetal monitoring for at least 24 hours. Thereafter, the remaining benzathine penicillin G doses can be given in an outpatient setting. The rate of maternal titer decline is not tied to pregnancy outcomes. Therefore, after adequate syphilotherapy, maternal titers should be checked monthly to ensure they are not increasing four-fold, as this may indicate reinfection or treatment failure.

Prevention of Allergic Reactions in Anesthetized Patients

Hypersensitivity reactions during perioperative period are increasing and may be potentially life-threatening. Therefore, major emphasis is given to prevention. We perform a review to examine which measures should be taken to prevent reactions to products used in elective and emergency surgery. Any patient with a history of previous anaphylaxis or severe reaction during anaesthesia should be referred to allergist for detection of the offending compound. However, the identification of the triggering agent is not always feasible because of the low accuracy of diagnostic tests. In these cases and when emergency surgery is required, it should be considered to replace all drugs administered before the onset of the reaction with alternatives. Furthermore, any cross-reacting agent and latex, especially in patients belonging to populations at-risk for latex allergy should be avoided. In susceptible patients, premedication with antihistamines and corticosteroids might reduce the severity of reaction to drugs or contrast material while it is unclear whether pre-treatment decreases incidence of anaphylactic reactions. There is no evidence that premedication prevents allergic reactions to latex. Overall, physicians should not rely on the efficacy of premedication.

Safety, Costs, and Efficacy of Rapid Drug Desensitizations to Chemotherapy and Monoclonal Antibodies

BACKGROUND

Rapid drug desensitization (RDD) is used to address hypersensitivity reactions to chemotherapeutics and monoclonal antibodies, allowing patients to be treated with optimal pharmacological agents. RDD protocols are tailored to each individual patient's reaction and needs, and protect against anaphylaxis, but overall risks, costs, and benefits have not been determined.

OBJECTIVE

We investigated the safety, efficacy, costs, and life expectancy of patients in a large population undergoing RDD.

METHODS

We analyzed 2177 RDD procedures performed in 370 patients with cancer, vasculitis, and hematological and connective tissue diseases who presented 402 reactions. A subgroup of carboplatin allergic patients with ovarian cancer treated with RDD was analyzed for costs and life expectancy and compared with a nonallergic control group.

RESULTS

RDD allowed all patients to receive safely the full dose of the medication to which they were reactive. A gradual increase in the fraction of outpatient desensitizations from 81% to 98% was achieved through risk stratification. Of the 2177 desensitizations, 93% had no or mild reactions whereas 7% had moderate to severe reactions, which did not preclude the completion of the treatment, and there were no deaths. Overall health costs in the carboplatin allergic group were not higher than those in the nonallergic group treated with standard of care. Administration of carboplatin through RDD was as effective as standard administration with a nonsignificant increase in life expectancy in desensitized patients as compared with nonallergic, nondesensitized controls.

CONCLUSIONS

RDD is cost effective and safe for allergic patients with cancer and chronic disease to remain on first line therapy.

Management of allergy to penicillins and other beta-lactams

The Standards of Care Committee of the British Society for Allergy and Clinical Immunology (BSACI) and an expert panel have prepared this guidance for the management of immediate and non-immediate allergic reactions to penicillins and other beta-lactams. The guideline is intended for UK specialists in both adult and paediatric allergy and for other clinicians practising allergy in secondary and tertiary care. The recommendations are evidence based, but where evidence is lacking, the panel reached consensus. During the development of the guideline, all BSACI members were consulted using a Web-based process and all comments carefully considered. Included in the guideline are epidemiology of allergic reactions to beta-lactams, molecular structure, formulations available in the UK and a description of known beta-lactam antigenic determinants. Sections on the value and limitations of clinical history, skin testing and laboratory investigations for both penicillins and cephalosporins are included. Cross-reactivity between penicillins and cephalosporins is discussed in detail. Recommendations on oral provocation and desensitization procedures have been made. Guidance for beta-lactam allergy in children is given in a separate section. An algorithm to help the clinician in the diagnosis of patients with a history of penicillin allergy has also been included.

Desensitization in delayed drug hypersensitivity reactions -- an EAACI position paper of the Drug Allergy Interest Group

Drug hypersensitivity may deprive patients of drug therapy, and occasionally no effective alternative treatment is available. Successful desensitization has been well documented in delayed drug hypersensitivity reactions. In certain situations, such as sulfonamide hypersensitivity in HIV-positive patients or hypersensitivity to antibiotics in patients with cystic fibrosis, published success rates reach 80%, and this procedure appears helpful for the patient management. A state of clinical tolerance may be achieved by the administration of increasing doses of the previously offending drug. However, in most cases, a pre-existent sensitization has not been proven by positive skin tests. Successful re-administration may have occurred in nonsensitized patients. A better understanding of the underlying mechanisms of desensitization is needed. Currently, desensitization in delayed hypersensitivity reactions is restricted to mild, uncomplicated exanthems and fixed drug eruptions. The published success rates vary depending on clinical manifestations, drugs, and applied protocols. Slower protocols tend to be more effective than rush protocols; however, underreporting of unsuccessful procedures is very probable. The decision to desensitize a patient must always be made on an individual basis, balancing risks and benefits. This paper reviews the literature and presents the expert experience of the Drug Hypersensitivity Interest Group of the European Academy of Allergy and Clinical Immunology.

Clinical applications of drug desensitization in the Asia-Pacific region

Drug desensitization is the induction, within hours to days, of a temporary state of tolerance to a drug which the patient has developed a hypersensitivity reaction to. It may be used for IgE and non-IgE mediated allergic reactions, and certain non-allergic reactions. The indication for desensitization is where no alternative medications are available for the treatment of that condition, and where the benefits of desensitization outweigh the risks. Desensitization is a therapeutic modality for drug allergy (similar to allergen specific immunotherapy for allergic rhinitis and insect venom anaphylaxis). In contrast, the drug provocation test is a diagnostic modality used to confirm or refute the diagnosis of drug allergy. This review discusses the clinical applications of desensitization for the treatment of common infectious, metabolic and cardiovascular diseases, and oncological conditions in the Asia-Pacific region.

Clinical immunology review series: an approach to desensitization

Allergen immunotherapy describes the treatment of allergic disease through administration of gradually increasing doses of allergen. This form of immune tolerance induction is now safer, more reliably efficacious and better understood than when it was first formally described in 1911. In this paper the authors aim to summarize the current state of the art in immunotherapy in the treatment of inhalant, venom and drug allergies, with specific reference to its practice in the United Kingdom. A practical approach has been taken, with reference to current evidence and guidelines, including illustrative protocols and vaccine schedules. A number of novel approaches and techniques are likely to change considerably the way in which we select and treat allergy patients in the coming decade, and these advances are previewed.

General considerations on rapid desensitization for drug hypersensitivity - a consensus statement

Drug hypersensitivity reactions can occur with most drugs, are unpredictable, may affect any organ or system, and range widely in clinical severity from mild pruritus to anaphylaxis. In most cases, the suspected drug is avoided in the future. However, for certain patients, the particular drug may be essential for optimal therapy. Under these circumstances, desensitization may be performed. Drug desensitization is defined as the induction of a temporary state of tolerance of a compound responsible for a hypersensitivity reaction. It is performed by administering increasing doses of the medication concerned over a short period of time (from several hours to a few days) until the total cumulative therapeutic dose is achieved and tolerated. It is a high-risk procedure used only in patients in whom alternatives are less effective or not available after a positive risk/benefit analysis. Desensitization protocols have been developed and are used in patients with allergic reactions to antibiotics (mainly penicillin), insulins, sulfonamides, chemotherapeutic and biologic agents, and many other drugs. Desensitization is mainly performed in IgE-mediated reactions, but also in reactions where drug-specific IgE have not been demonstrated. Desensitization induces a temporary tolerant state, which can only be maintained by continuous administration of the medication. Thus, for treatments like chemotherapy, which have an average interval of 4 weeks between cycles, the procedure must be repeated for every new course. In this paper, some background information on rapid desensitization procedures is provided. We define the drugs and drug reactions indicated for such procedures, describe the possible mechanism of action, and discuss the indications and contraindications. The data should serve as background information for a database (accessible via the EAACI-homepage) with standardized protocols for rapid desensitization for antibiotics, chemotherapeutic agents, monoclonal antibodies/fusion proteins, and other drugs.

Glatiramer acetate: successful desensitization for treatment of multiple sclerosis

BACKGROUND

Glatiramer acetate is an immunomodulatory drug that is widely prescribed for the treatment of multiple sclerosis. It is frequently associated with local injection site reactions and generalized urticaria. It is also associated with immediate postinjection systemic reactions in approximately 10% of patients. To our knowledge, no desensitization protocols for glatiramer acetate have been published to date.

OBJECTIVES

To evaluate the safety and efficacy of glatiramer acetate desensitization in a series of patients with multiple sclerosis.

METHODS

Six patients with multiple sclerosis and glatiramer acetate-associated local or systemic reactions underwent a 4-hour outpatient desensitization procedure at Cleveland Clinic between 2003 and 2008. Beginning with 20 ng, we administered subcutaneous glatiramer acetate suspension in increasing dosages every 15 minutes. Patient outcomes were monitored by return clinic visit and telephone follow-up.

RESULTS

No episodes of anaphylaxis or serious adverse reactions occurred during or immediately after desensitization. One patient suspended therapy after 14 months due to persistent local injection site reactions. All other patients successfully continued glatiramer acetate therapy.

CONCLUSION

Glatiramer acetate offers significant benefit to patients with multiple sclerosis. Our experience suggests that patients who suspend its use owing to local or systemic reactions can be successfully and safely desensitized and can resume medication use. To our knowledge, this is the first report of successful desensitization to glatiramer acetate in patients with multiple sclerosis.

Desensitization therapy for allergic reactions to antituberculous drugs

OBJECTIVE

We retrospectively evaluated the clinical usefulness of desensitization therapy for many patients showing allergic reactions to anti-mycobacterial drugs (INH and RFP) according to the proposition reported by the Japanese Society for Tuberculosis (JST).

METHODS

Desensitization therapy for anti-mycobacterial drugs was performed according to the propositions of JST for forty-six patients with mycobacterial disease in several hospitals participating in the Chugoku-Shikoku Mycobacterial Disease Committee between January 1999 and December 2009.

RESULTS

Adverse reactions occurred as drug-induced skin eruptions in 23 patients, drug-induced fever in 16, and drug-induced fever plus eruption in 7. The causative drugs suggested by the clinical course or DLST were RFP in 30 patients and INH in 16. The clinical effects of desensitization therapy for individual drugs was good in 23 of 30 patients (77%) receiving RFP, and in 13 of 16 (81%) receiving INH. Ten patients showing failure of desensitization included 5 elderly patients and 2 patients with a history of drug allergies. The interval until initiation of desensitization therapy ranged from 5 to 30 days after the disappearance of adverse reactions and the interval until the appearance of adverse reactions during desensitization therapy ranged from 3 to 18 days. A comparative study between the patient group with successful desensitization therapy and that with failure of desensitization did not show any significant differences except for the interval until initiation of desensitization therapy.

CONCLUSION

We confirmed the clinical effectiveness of desensitization therapy for anti-mycobacterial drugs according to the propositions of JST in this multicenter study.

Reexamining syphilis: an update on epidemiology, clinical manifestations, and management

OBJECTIVE

To review the epidemiology, clinical features, diagnosis, and treatment of syphilis.

DATA SOURCES

Studies and reviews were abstracted from MEDLINE (1950-April 2007) using the search term syphilis. All papers were cross-referenced to identify additional studies and reviews for inclusion.

STUDY SELECTION AND DATA EXTRACTION

Pertinent original research articles, review articles, and book chapters were evaluated.

DATA SYNTHESIS

Syphilis is a spirochetal disease that has plagued mankind for centuries. Following a low incidence of syphilis in the US for the last 2 decades, rates are now increasing both in the US and other parts of the world. Once acquired, syphilis can pass through 4 distinct stages of disease: primary syphilis, secondary syphilis, latent syphilis, and tertiary syphilis, with each stage being characterized by different symptoms and levels of infectivity. Diagnosis is made primarily by serologic assays with nontreponemal tests such as the Venereal Disease Research Laboratory and the Rapid Plasma Reagin assay used for screening. Treponemal tests including the Treponema pallidum particle agglutination and the fluorescent treponemal antibody absorption test are then used for confirmation. Recommended treatment regimens are based largely on uncontrolled trials and clinical experience. Penicillin is the treatment of choice, with the preparation and treatment duration varying for different stages. Benzathine penicillin is the treatment of choice for all stages of syphilis except neurosyphilis, for which aqueous crystalline penicillin or procaine penicillin is used due to the central nervous system penetration of these formulations. Coinfection with both syphilis and HIV occurs frequently due to common risk factors. These 2 diseases interact with each other, making both diagnosis and treatment more complicated.

CONCLUSIONS

Clinicians should be aware of the signs and symptoms of syphilis as well as current guidelines for the management and treatment of this disease.

Desensitization for drug allergy

PURPOSE OF REVIEW

Desensitization for drug allergy is the induction of temporary clinical unresponsiveness to drug antigens. Gradual reintroduction of small doses of drug antigen at fixed time intervals allows for the delivery of full therapeutic doses, protecting patients from anaphylaxis. Rapid desensitizations permit the use of essential antibiotics in severely infected allergic patients or aspirin in aspirin-sensitive cardiac patients undergoing revascularization. We review the indications and outcomes of recent protocols for desensitization to antibiotics and aspirin.

RECENT FINDINGS

Despite the success of rapid desensitizations, the cellular and molecular inhibitory mechanisms are incompletely understood. In-vitro mast cell and basophil models implicate molecular signaling molecules syk and STAT6. Rapid desensitization protocols treat type I mast cell/IgE dependent reactions, such as anaphylaxis, as seen with sensitization to penicillin, cephalosporins, and other antibiotics. Anaphylactoid reactions induced upon initial drug exposure and with similar clinical presentation as immunoglobulin E-mediated reactions, as seen with aspirin, vancomycin and taxenes, can also be treated with rapid desensitizations.

SUMMARY

Successful rapid desensitization protocols for treating adverse reactions to antibiotics and aspirin allow for treatment of critically infected patients and aspirin-sensitive cardiac patients. Standardized protocols with high success rates should be implemented as the standard of care.

Mechanism for acute oral desensitization to antibiotics

BACKGROUND

Despite the widespread use of an acute oral desensitization procedure in patients with allergic reactions to a variety of antibiotics, the precise mechanism of this procedure is poorly understood.

OBJECTIVE

To investigate the mechanisms underlying acute oral desensitization to antibiotics.

METHODS

Using a murine model of active systemic anaphylaxis to penicillin V (Pen V), mice previously sensitized to Pen V were desensitized by oral feeding of Pen V. The dose was doubled every 15 min and five feedings were given. The achievement of acute oral desensitization was evaluated by induction of active systemic and active cutaneous anaphylaxis, and by measuring the plasma levels of platelet-activating factor and histamine. Antigen-specific serum IgE antibody (Ab) levels were determined by passive cutaneous anaphylaxis.

RESULTS

Mice fed more than 3 mg of cumulative dose of Pen V were completely protected from fatal systemic anaphylactic reaction and the desensitized state lasted approximately 1 h. Antigen-specific mast cell desensitization, but not hapten inhibition, consumption of IgE Abs, or depletion of mast cell mediators, occurred during acute oral desensitization.

CONCLUSIONS

Acute oral desensitization to Pen V occurred in the mice, and antigen-specific mast cell desensitization was associated with the underlying mechanism for oral desensitization.

Immediate Hypersensitivity to Rifampicin in 3 Patients: Diagnostic Procedures and Induction of Clinical Tolerance

BACKGROUND

Desensitization with drugs may be indicated in some clinical situations. Apart from large experiences with beta-lactam antibiotics and cotrimoxazole in HIV infection, experience with other drugs is limited. Rifampicin may elicit exanthema and urticaria, and their pathomechanisms are not known in detail. Since therapy with rifampicin may be indispensable in mycobacterial infections or against multiresistant Staphylococcus aureus, desensitization may be indicated in some patients.

OBJECTIVE

Report of immediate hypersensitivity to rifampicin and description of diagnostic and desensitization procedures.

METHODS

We report 3 patients with immediate urticarial reactions to rifampicin. Diagnostic procedures included skin and in vitro tests (specific IgE, lymphocyte transformation test, LTT, and CAST). The non-irritant cutoff concentration was evaluated in 24 volunteers. A 7-day desensitization procedure was used.

RESULTS

Only intradermal tests at a dilution of at least 1:10,000 (concentration of rifampicin approximately 0.006 mg/ml) were true positive, whereas in vitro tests (IgE, LTT and CAST) did not correctly identify hypersensitive patients. Two patients had positive accidental reexposure. All patients were successfully desensitized with rifampicin according to a slow 7-day protocol.

CONCLUSIONS

Rifampicin rarely elicits immediate hypersensitivity symptoms which may be diagnosed by intradermal skin tests. In vitro tests did not contribute to the diagnosis. Therefore, an IgE-mediated mechanism remains to be proven. Desensitization with rifampicin using different protocols has been reported. In our 3 cases, clinical tolerance to rifampicin was achieved using a 7-day protocol.

Intravenous Linezolid Administered Orally: A Novel Desensitization Strategy

A 41-year-old woman with a history of myasthenia gravis was admitted to a local hospital because of severe muscle weakness, ptosis, shortness of breath, nausea and vomiting, and fever. Blood cultures revealed Enterococcus faecium resistant to several antimicrobial agents. The organism had minimum inhibitory concentrations above 16 microg/ml for vancomycin and above 2 microg/ml for quinupristin-dalfopristin. In the absence of therapeutic alternatives, treatment with linezolid was required (minimum inhibitory concentration 1.5 microg/ml). The first dose of linezolid resulted in a hypersensitivity reaction consistent with an immunoglobulin E-mediated response requiring medical intervention. Because of a lack of intravenous access and because of limited availability of the oral suspension from the manufacturer, a desensitization protocol was implemented in which the intravenous formulation of linezolid was given orally. The patient was successfully desensitized by using an escalating, 14-dose procedure. We believe this is the first case in the English language literature to describe successful desensitization with the oral administration of intravenous linezolid in a patient with E. faecium bacteremia who was allergic to oxazolidinone.

Antigen-IgE desensitization in signal transducer and activator of transcription 6-deficient mast cells by suboptimal doses of antigen

BACKGROUND

Rapid administration of suboptimal antigen induces transient unresponsiveness in patients with IgE antibodies to beneficial medications, but the molecular mechanisms of desensitization are poorly understood. Mast cells (MCs) have been implicated as the target cells.

OBJECTIVE

To establish a physiologic model of IgE-antigen desensitization using mouse bone marrow-derived MCs (mBMMCs) from wild-type and signal transducer and activator of transcription 6 (STAT6)-deficient mice.

METHODS

The mBMMCs were sensitized with dinitrophenyl (DNP) IgE or trinitrophenyl (TNP) IgE and activated with DNP/TNP-human serum albumin. For desensitization, suboptimal doses of DNP/TNP-human serum albumin were administered at fixed intervals.

RESULTS

Desensitized mBMMCs failed to respond to an optimal dose of antigen, indicating successful desensitization. Desensitization was time dependent, with 5 minutes of antigen exposure being optimal. Resensitization with DNP-IgE did not reverse the process. The desensitized cells were responsive to calcium ionophore and phorbol myristate acetate. Thus, the desensitization reaction alters an early event in the high-affinity IgE receptor (FcepsilonRI)-dependent signaling pathway in a nontoxic manner. The mBMMCs from STAT6-null mice could not be desensitized by suboptimal doses of antigen.

CONCLUSIONS

Mast cells can be rendered unresponsive by rapid administration of suboptimal doses of antigen in the presence of calcium, similar to in vivo desensitizations. The STAT6-null mBMMCs cannot be desensitized, providing the first molecular target in this inhibitory process.

Dilemmas and controversies in penicillin allergy

Since the initial reports of penicillin and beta-lactam drugs causing allergic reactions, much has been elucidated regarding their pathophysiology and mechanism of action. Despite advances in testing for penicillin allergy, with IgE antibodies and skin tests available for the major and minor determinants of penicillin, these reactions remain a challenge to all physicians. They have characteristically been classified according to mechanism and time. Herein, the authors propose a classification system of penicillin allergy based on immunologic mechanisms.

Drug desensitization

Although most patients who report a history of drug allergy are not truly allergic, this article focuses on those individuals with confirmed drug hypersensitivity. Desensitization is an immunologic method that allows allergic patients to receive the sensitizing drug safely. Classically, the procedure is applied in IgE-mediated reactions, but its use has been extended to other drug reactions. The most common clinical scenarios wherein desensitization may be needed are reviewed. The discussion includes rapid desensitization of patients with IgE-mediated allergies to penicillin and other classes of antibiotics, and sulfonamide desensitization of HIV-positive patients.

Anaphylaxis during surgical and interventional procedures

OBJECTIVE

To describe the current evidence-based knowledge of the causes, diagnostic evaluation, and treatment of patients with anaphylaxis associated with surgical and interventional procedures.

DATA SOURCES

Articles published between 1966 and 2003 were identified in MEDLINE using the keywords anaphylactoid, anaphylaxis, anesthetics, antibiotics, cephalosporins, contrast media, colloids, flow cytometry, hypersensitivity, latex, neuromuscular depolarizing agents, neuromuscular nondepolarizing agents, penicillins, radioallergosorbent test, skin test, and vancomycin. Additional studies were identified from article reference lists.

STUDY SELECTION

Relevant, peer-reviewed original research articles and reviews.

RESULTS

Neuromuscular blocking agents, natural rubber latex, antibiotics, and induction agents are the most common causes of anaphylaxis during surgical and interventional procedures. Colloids, opioids, and radiocontrast media probably account for less than 10% of all reactions. Newer agents implicated in anaphylaxis include isosulphan blue and chlorhexidine. Skin tests are useful for evaluating allergic reactions to anesthetic agents and penicillins and for selecting alternative agents. Skin testing and specific IgE measurements for latex vary in allergen standardization and sensitivity and specificity, respectively. Flow cytometric allergen stimulation tests show promise in differentiating allergic from idiosyncratic ("pseudoallergic") reactions. Drug desensitization has been shown to be useful for penicillin anaphylaxis. Premedication with histamine receptor antagonists and corticosteroids helps prevent or attenuate radiocontrast media reactions.

CONCLUSIONS

Anaphylaxis during surgical and interventional procedures may be difficult to evaluate because of the rapid, successive use of multiple drugs or diagnostic agents. Careful analysis of anesthetic records and diagnostic tests for all the putative agents are necessary to ensure a complete evaluation.

Antibiotic desensitization for the allergic patient: 5 years of experience and practice

BACKGROUND

Antibiotic desensitization is an option for patients with suspected IgE-mediated antibiotic allergy when no other alternative exists for treating life-threatening bacterial infections. However, there are limited data describing the outcomes of this procedure with newer, commonly used antibiotics.

OBJECTIVE

To evaluate the safety and utility of antibiotic desensitization.

METHODS

We retrospectively reviewed the medical records of all patients undergoing antibiotic desensitization in our institution between November 1996 and November 2001.

RESULTS

There were a total of 57 desensitizations performed in 21 patients. The mean age of the patients was 22.8 years (range, 1.9-44.5 years) and 15 (71%) were female. Nineteen (90%) of the 21 patients had been diagnosed as having cystic fibrosis. In 33 (100%) of 33 desensitizations to unique antibiotics that occurred during the study period, the indication for desensitization was a history suggestive of an IgE-mediated reaction to the antibiotic and/or a positive skin test result to the antibiotic or a known cross-reactive antibiotic. Desensitizations were performed to 12 different antibiotics. Successful outcomes were achieved in 43 desensitizations (75%). Of the 11 cases (19%) that were terminated due to an allergic reaction, there were no fatalities, intubations, or other aggressive interventions besides the use of epinephrine, antihistamines, and corticosteroids. In 7 of 11 unsuccessful desensitizations, a non-IgE mechanism appeared to be responsible for the allergic reaction.

CONCLUSIONS

Antibiotic desensitization is a useful option when treating patients with life-threatening infections who must receive antibiotics to which they have an IgE-mediated allergy. These data indicate that in most cases, patients with presumed IgE-mediated antibiotic allergy may safely receive antibiotics after desensitization.

Anaphylaxis during the perioperative period

Anesthesiologists use a myriad of drugs during the provision of an anesthetic. Many of these drugs have side effects that are dose related, and some lead to severe immune-mediated adverse reactions. Anaphylaxis is the most severe immune-mediated reaction; it generally occurs on reexposure to a specific antigen and requires the release of proinflammatory mediators. Anaphylactoid reactions occur through a direct non-immunoglobulin E-mediated release of mediators from mast cells or from complement activation. Muscle relaxants and latex account for most cases of anaphylaxis during the perioperative period. Symptoms may include all organ systems and present with bronchospasm and cardiovascular collapse in the most severe cases. Management of anaphylaxis includes discontinuation of the presumptive drug (or latex) and anesthetic, aggressive pulmonary and cardiovascular support, and epinephrine. Although a serum tryptase confirms the diagnosis of an anaphylactic reaction, the offending drug can be identified by skin-prick, intradermal testing, or serologic testing. Prevention of recurrences is critical to avoid mortality and morbidity.

Antibiotic desensitization in adults with cystic fibrosis

OBJECTIVE

Allergic reactions to antibiotics occur in up to 30% of patients with cystic fibrosis (CF). Repeated antibiotic exposure and immune hyper-responsiveness increase the risk of allergic reactions and may limit antibiotic choice. Desensitization may allow the successful administration of an antibiotic despite previous allergy. We aimed to determine the success of antibiotic desensitization in patients with CF in an adult CF unit over a 7-year period.

METHODOLOGY

A retrospective medical record review was performed on the 19 patients who had undergone antibiotic desensitization procedures. Data collected included drug allergy and intolerance profiles, nature of allergies, and the outcome of desensitization procedures. Desensitization procedures were performed in a ward setting according to published methods.

RESULTS

Nineteen patients (13 females) reported 62 drug allergies with a mean of 3.3 per patient. Of the 71 desensitization procedures undergone by this group, 54 (76%) were successful. Fifteen of the 19 patients were allergic to two or more beta-lactam antibiotics. Over half of the patients were desensitized to more than one antibiotic. Nine different antibiotics were used in 31 different patient/drug combinations. A successful outcome was achieved in 18/31 (58%) combinations, with three requiring treatment for mild allergic reactions. Allergic reactions caused drug cessation in a total of 19 patient/drug combinations (three after initial successful desensitization and full courses of antibiotics). Over 50% of these reactions occurred on day 1. Desensitization failures were more common in patients with well-documented allergic reactions to a specific drug.

CONCLUSION

This study demonstrates that multiple antibiotic allergies are common in adults with CF. Cross-reactivity between beta-lactam antibiotics may limit antibiotic choice for the treatment of pulmonary exacerbations. Antibiotic desensitization allows safe and successful treatment in the ward setting of many patients with previous allergies to an antibiotic. In many patients symptoms of allergy still occur and result in cessation of the antibiotics. Use of corticosteroids and antihistamines may improve the success rate of desensitization procedures.

Penicillin allergy: prevalence of vague history in skin test-positive patients

OBJECTIVE

Penicillin (PCN) skin testing is a reliable tool for predicting which patients can safely receive the antibiotic. Depending on the study, 7% to 76% of patients who have a history of PCN allergy have positive PCN skin tests. Many physicians approach patients who have a vague history of PCN allergy less cautiously than they approach those who have a convincing history suggestive of an IgE-mediated reaction. We reviewed the published literature to determine how many patients who had a history of PCN allergy and who were skin test-positive had a vague history of allergy.

DATA SOURCES

By cross-referencing the keywords "penicillin" and "skin test," an Ovid MEDLINE search for English language studies published from 1966 to 1998 was performed.

STUDY SELECTION

Studies in which history positive/skin test-positive patients were identified, and which contained documentation of the type of previous reaction in these patients, were included in the analysis. The MEDLINE search revealed 295 English language articles, of which 27 fulfilled the inclusion criteria. Three additional studies published prior to 1966 (and therefore not available through MEDLINE) also were found, bringing the total to 30. A "convincing" history was defined to be one likely to be IgE-mediated (such as anaphylaxis, urticaria, angioedema or pruritic rash). A "vague" history was one unlikely to be IgE-mediated (such as maculopapular rash, GI symptoms, or an unknown reaction).

RESULTS

Overall, 347/1063, or 33%, of history positive/skin test-positive patients had a vague PCN allergy history, with a range of 0% to 70% among the 30 studies.

CONCLUSION

A large proportion of patients who have PCN-specific IgE antibodies, as determined by skin testing, have vague PCN allergy histories. These results therefore, indicate that, like patients with convincing histories, patients with vague allergic histories should undergo PCN skin testing prior to PCN administration.

The penicillins

The penicillin family of antibiotics remains an important part of our antimicrobial armamentarium. In general, these agents have bactericidal activity, excellent distribution throughout the body, low toxicity, and efficacy against infections caused by susceptible bacteria. The initial introduction of aqueous penicillin G for treatment of streptococcal and staphylococcal infections was an important pharmacologic landmark. The emergence of penicillinase-producing Staphylococcus aureus prompted the development of the penicillinase-resistant penicillins (for example, methicillin, oxacillin, and nafcillin), in which an acyl side chain prevented disruption of the beta-lactamase ring. Subsequently, the aminopenicillins (ampicillin, amoxicillin, and bacampicillin) were developed because of the need for gram-negative antimicrobial activity. Their spectrum initially included Escherichia coli, Proteus mirabilis, Shigella, Salmonella, Listeria, Haemophilus, and Neisseria. The search for a penicillin with additional antimicrobial activity against the Enterobacteriaceae and Pseudomonas aeruginosa led to the development of the carboxypenicillins (carbenicillin and ticarcillin) and the ureidopenicillins (mezlocillin, azlocillin, and piperacillin). Finally, the combination of a beta-lactamase inhibitor (clavulanic acid, sulbactam, or tazobactam) and an aminopenicillin, ticarcillin, or piperacillin has further extended their antibacterial spectra by inhibiting certain beta-lactamases (non-group 1) of resistant bacteria. The development of an ideal penicillin that is rapidly bactericidal, nonsensitizing, nontoxic, bioavailable, and resistant to beta-lactamases and that has a high affinity for penicillin-binding proteins remains the goal.