Sulfonamide allergies and outcomes related to use of potentially cross-reactive drugs in hospitalized patients

Impact of Sulfonamide Allergy Label on Clinical Outcomes in Patients with Pneumocystis jirovecii Pneumonia

INTRODUCTION

The presence of antibiotic allergy labels can have harmful impacts on clinical outcomes, particularly among immunosuppressed patients, in whom there have been associations with increased complications, readmission rates, and mortality. We explore the effects of a sulfonamide allergy label (SAL) on clinical outcomes in adult patients with Pneumocystis jirovecii pneumonia (PJP).

METHODS

In this retrospective matched cohort study, we utilized TriNetX, a multicenter national database, to match 535 adult patients with PJP and SAL to an equal number of controls. We identified cases indexed between 01/01/2010 and 01/01/2023 utilizing ICD-10 codes for PJP and allergy status to sulfonamides and through detection of P. jirovecii antigen with immunofluorescence or PCR. Propensity score matching was performed in a 1:1 fashion for demographics and comorbidities, and our analysis included clinical outcomes that occurred within 30 days after the occurrence of the index event.

RESULTS

While hospitalization risk tended to be lower among patients with SAL as compared to controls (RR: 0.90; 95% CI 0.81-1.01), there were no major differences in the risk of respiratory failure (RR: 0.94; 95% CI 0.84-1.05), prednisone use (RR: 1; 95% CI 0.91-1.10), intensive level of care requirement (RR: 0.85; 95% CI 0.69-1.06), intubation (RR: 0.85; 95% CI 0.61-1.19), or mortality (RR: 0.98; 95% CI 0.68-1.42). The presence of SAL did however impact antibiotic prescription patterns, with an underutilization of trimethoprim (RR: 0.50; 95% CI 0.43-0.59) and sulfamethoxazole (RR, 0.47; 95% CI 0.40-0.56) and overuse of alternative agents by patients with SAL as compared to controls. Yet, there was no difference in the occurrence of adverse outcomes such as hepatotoxicity (RR: 1.09; 95% CI 0.49-2.45) or acute kidney injury (RR: 0.94; 95% CI 0.78-1.14) between patients with SAL and controls.

CONCLUSIONS

The presence of SAL alters antibiotic prescription patterns among adults with Pneumocystis infection but has no clinically significant impact on outcomes.

The Use of Thiazide Diuretics for the Treatment of Hypertension in Patients With Advanced Chronic Kidney Disease

The use of thiazide diuretics for the treatment of hypertension in patients with advance chronic kidney disease. Thiazides have been recommended as the first-line for the treatment of hypertension, yet their use has been discouraged in advanced chronic kidney disease (CKD), as they are suggested to be ineffective in advanced CKD. Recent data suggest that thiazide diuretics may be beneficial blood pressure control in addition to natriuresis in existing CKD. This review discusses the commercially available thiazides with a focus on thiazide pharmacology, most common adverse effects, clinical uses of thiazide diuretic, and the evidence for efficacy of thiazide use in advanced CKD.

Sulfonamide Allergies

As one of the earliest developed antimicrobial classes, sulfonamides remain important therapeutic options for the empiric and definitive treatment of various infectious diseases. In the general population, approximately 3–8% of patients are reported to experience a sulfonamide allergy. Sulfonamide allergies can result in various physical manifestations; however, rash is reported as the most frequently observed. In patients with human immunodeficiency virus (HIV), dermatologic reactions to sulfonamide antimicrobial agents occur 10 to 20 times more frequently compared to immunocompetent patients. This article describes the incidence, manifestations, and risk factors associated with sulfonamide allergies. The potential for cross-reactivity of allergies to sulfonamide antimicrobials with nonantimicrobial sulfonamide medications is also reviewed. Data suggest that substitutions at the N₁ and N₄ positions are the primary determinants of drug allergy instead of the common sulfonamide moiety. For patients with an indication for a sulfonamide antimicrobial with a listed allergy, it is important for healthcare practitioners to adequately assess the allergic reaction to determine appropriate management. Rechallenge and desensitization strategies may be appropriate for patients with delayed maculopapular eruptions, while alternative treatment options may be prudent for more severe reactions. Available data suggests a low risk of cross-allergenicity between sulfonamide antimicrobial and nonantimicrobial agents.

Assessment of Opioid Cross-reactivity and Provider Perceptions in Hospitalized Patients With Reported Opioid Allergies

Background: The incidence of opioid allergy cross-reactivity in hospitalized patients with historical opioid allergies remains unknown. Objectives: The purpose of this study was to characterize the incidence of newly suspected IgE-mediated reactions (IMRs) based on clinical criteria among patients with a chart-documented opioid allergy and to assess clinician perceptions of opioid allergies. Methods: This retrospective cohort study was conducted in hospitalized adults with a historically documented opioid allergy who received a subsequent opioid. The primary outcome was the incidence of allergic cross-reactivity between clinical and chemical opioid classes in patients with historical IMRs (H-IMRs) identified by clinical criteria, ICD-9 diagnosis codes, or allergic reaction treatment. Secondary outcomes included the incidence of opioid intolerances incorrectly documented as allergies and a survey to clinicians to assess the impact of opiate warnings on prescribing practices. Results: A total of 499 patients with historical opioid allergies were included. H-IMR to an opioid of any class was not significantly associated with IMR cross-reactivity to the same or any other class, with cross-reactivity rates ranging from 0% to 6.7%. Of the historical chart-documented allergies, 249 reactions (50%) were determined to be intolerances. A total of 461 (92.5%) patients successfully tolerated readministration of opioids despite a chart-documented allergy, and 8 (1.6%) patients developed possible IMR (7 pruritus, 1 possible anaphylaxis). Survey results (n = 54) indicated that opiate allergy warnings were neutral or unlikely to change opiate prescribing. Conclusions: The risk of IMRs caused by opioids is low in patients with H-IMRs to opioids. Opioid allergy documentations may propagate alert fatigue and unwarranted prescribing changes.

Sulfonamide Drug Allergy

PURPOSE OF REVIEW

We sought to review past and current literature on sulfonamide drug allergy and distill it in a practical manner to assist the clinician, specifically focusing on cross-reactivity and desensitization.

RECENT FINDINGS

There do not appear to be consistent genetic markers to reliably predict features of or the presence hypersensitivity reactions. Recent evidence continues to alleviate early concerns cross-reactivity between sulfonamide antibiotics and non-antibiotics. Sulfonamide drug allergy is frequently encountered by the practicing clinician. For sulfonamide antibiotics, delayed rash is the most common clinical manifestation. There is no current evidence to support avoidance of all non-antibiotic sulfonamides in those with a reported allergy to sulfonamide antibiotics, although certain scenarios require caution. Available evidence supports the cautious reintroduction of sulfonamide antibiotics via desensitization, which is usually well tolerated and should be considered in those with strong indications for trimethoprim-sulfamethoxazole and a reported sulfonamide allergy.

Delayed Cutaneous Hypersensitivity Reactions to Antibiotics: Management with Desensitization

Successful desensitization to mild to moderate delayed cutaneous adverse reaction to antibiotics has been described in a limited number of antibiotics and found to be safe. However, there are ample opportunities to standardize protocols for delayed cutaneous adverse reactions to antibiotics.

Mechanisms of Action of Vitamin D as Supplemental Therapy for Pneumocystis Pneumonia

The combination of trimethoprim and sulfamethoxazole (TMP-SMX) is the most effective regimen for therapy of Pneumocystis pneumonia (PCP). As many patients with PCP are allergic or do not respond to it, efforts have been devoted to develop alternative therapies for PCP. We have found that the combination of vitamin D₃ (VitD3) (300 IU/kg/day) and primaquine (PMQ) (5 mg/kg/day) was as effective as TMP-SMX for therapy of PCP. In this study, we investigated the mechanisms by which vitamin D enhances the efficacy of PMQ. C57BL/6 mice were immunosuppressed by CD4⁺ cell depletion, infected with Pneumocystismurina for 8 weeks, and then treated for 9 days with the combination of VitD3 and PMQ (VitD3-PMQ) or with TMP-SMX or PMQ to serve as controls. The results showed that vitamin D supplementation increased the number of CD11c⁺ cells, suppressed the production of proinflammatory cytokines (tumor necrosis factor alpha [TNF-α], gamma interferon [IFN-γ], and interleukin-6 [IL-6]) and inducible nitric oxide synthase (iNOS), and enhanced the expression of genes related to antioxidation (glutathione reductase and glutamate-cysteine ligase modifier subunit), antimicrobial peptides (cathelicidin), and autophagy (ATG5 and beclin-1). These results suggest that the main action of vitamin D is enhancing the ability of the host to defend against Pneumocystis infection.

Typical antimicrobials induce mast cell degranulation and anaphylactoid reactions via MRGPRX2 and its murine homologue MRGPRB2

Mast cells are unique immune cells that function as sentinels in host defence reactions, including immediate hypersensitivity responses and allergic responses. The mast cell-specific receptor named MAS-related G protein-coupled receptor X2 (MRGPRX2) triggers mast-cell degranulation, a key process in anaphylactoid reactions. It is widely observed that antimicrobials can induce pseudo-allergic reactions (i.e. IgE-independent mechanism) with symptoms ranging from skin inflammation to life-threatening systemic anaphylaxis. However, their direct involvement and the mechanisms underlying anaphylactoid reactions caused by antimicrobials have not been demonstrated. Structurally different antimicrobials were screened by Ca²⁺ imaging using MRGPRX2 overexpressing HEK293 cells. MRGPRX2 related anaphylactoid reactions induced by these components were investigated by body temperature drop and mast cell degranulation assays. We showed that MRGPRX2 is involved in allergic-like reactions to three types of antimicrobials in a dose-dependent manner. However, mast cells lacking the receptor show reduced degranulation. Furthermore, mice without MAS-related G protein-coupled receptor B2 (the orthologous gene of MRGPRX2) exhibited reduced substance-induced inflammation. Interestingly, β-lactam and antiviral nucleoside analogues did not induce anaphylactic reactions, which were also observed in vitro. These results should alarm many clinicians that such drugs might induce anaphylactoid reactions and provide guidance on safe dosage of these drugs.

Quantum chemical investigation on photodegradation mechanisms of sulfamethoxypyridazine with dissolved inorganic matter and hydroxyl radical

Sulfamethoxypyridazine (SMP) is one of the commonly used sulfonamide antibiotics (SAs). SAs are mainly studied to undergo triplet-sensitized photodegradation in water under natural sunlight with other coexisting aquatic environmental organic pollutants. In this work, SMP was selected as a representative of SAs. We studied the mechanisms of triplet-sensitized photodegradation of SMP and the influence of selected dissolved inorganic matter, i.e., anions (Br^-, Cl^-, and NO₃^-) and cations ions (Ca²⁺, Mg²⁺, and Zn²⁺) on SMP photodegradation mechanism by quantum chemical methods. In addition, the degradation mechanisms of SMP by hydroxyl radical (OH) were also investigated. The creation of SO₂ extrusion product was accessed with two different energy pathways (pathway-1 and pathway-2) by following two steps (step-I and step-II) in the triplet-sensitized photodegradation of SMP. Due to low activation energy, the pathway-1 was considered as the main pathway to obtain SO₂ extrusion product. Step-II of pathway-1 was measured to be the rate-limiting step (RLS) of SMP photodegradation mechanism and the effect of the selected anions and cations was estimated for this step. All selected anions and cations promoted photodegradation of SMP by dropping the activation energy of pathway-1. The estimated low activation energies of different degradation pathways of SMP with OH radical indicate that OH radical is a very powerful oxidizing agent for SMP degradation via attack through benzene derivative and pyridazine derivative ring.

Density functional theory study of direct and indirect photodegradation mechanisms of sulfameter

Sulfonamide antibiotics (SAs) have been observed to undergo direct and indirect photodegradation in natural water environments. In this study, the density functional theory (DFT) method was employed for the study of direct and indirect photodegradation mechanisms of sulfameter (SME) with excited triplet states of dissolved organic matter ((3)DOM(*)) and metal ions. SME was adopted as a representative of SAs, and SO2 extrusion product was obtained with different energy paths in the triplet-sensitized photodegradation of the neutral (SME(0)) and the anionic (SME(-)) form of SME. The selected divalent metal ions (Ca(2+), Mg(2+), and Zn(2+)) promoted the triplet-sensitized photodegradation of SME(0) but showed an inhibitory effect in triplet-sensitized photodegradation of SME(-). The triplet-sensitized indirect photodegradation mechanism of SME was investigated with the three DOM analogues, i.e., 2-acetonaphthone (2-AN), fluorenone (FN), and thioxanthone (TN). Results indicated that the selected DOM analogues are highly responsible for the photodegradation via attacking on amine moiety of SME. According to the natural bond orbital (NBO) analysis, the triplet-sensitized photodegradation mechanism of SME(0) with 2-AN, FN, and TN was H-transfer, and the SME(-) was proton plus electron transfer with these DOM analogues.

Sulfonamide Allergy and Possible Cross-Reactivity

True allergic reactions are IgE-mediated immune reactions and are also termed type I reactions, where the spectrum of presentation may range from urticaria to severe anaphylactic shock. Currently, 3% of the patients who use sulfonamide antibiotics develop an allergic reaction, with the most common being the development of a maculopapular rash. Sulfonamides are chemical compounds that can be further divided into 3 groups based on differences in their structural makeup. Several cases reviewing the cross-reactivity between sulfonamide antibiotics and nonantibiotics have suggested an increased risk of cross-reactivity and therefore recommend other treatment strategies to avoid a possible anaphylactic reaction; however, other reports argue that patients with a history of sulfonamide allergy who received sulfonamide nonantibiotics did not experience any adverse reactions. Pertinent data extracted from these studies are reviewed and evaluated.

Vitamin D as Supplemental Therapy for Pneumocystis Pneumonia

The combination of all-trans retinoic acid (ATRA) and primaquine (PMQ) has been shown to be effective for therapy of Pneumocystis pneumonia (PCP). Since a high concentration of ATRA has significant adverse effects, the possibility that vitamin D can be used to replace ATRA for PCP therapy was investigated. C57BL/6 mice were immunosuppressed by depleting CD4(+) cells and infected with Pneumocystis murina 1 week after initiation of immunosuppression. Three weeks after infection, the mice were treated orally for 3 weeks with vitamin D3 (VitD3) alone, PMQ alone, a combination of VitD3 and PMQ (VitD3-PMQ), or a combination of trimethoprim and sulfamethoxazole (TMP-SMX). Results showed that VitD3 (300 IU/kg/day) had a synergistic effect with PMQ (5 mg/kg/day) for therapy of PCP. Flow cytometric studies showed that this VitD3-PMQ combination recovered the CD11b(low) CD11c(high) alveolar macrophage population in mice with PCP as effectively as TMP-SMX. The VitD3-PMQ combination also reduced the massive infiltration of inflammatory cells into the lungs and the severity of lung damage. VitD3 was also shown to reduce the dose of TMP-SMX required for effective treatment of PCP. Taken together, results of this study suggest that a VitD3-PMQ combination can be used as an alternative therapy for PCP.

Treatment of brucellosis in a young child with trimethoprim/sulfamethoxazole anaphylaxis

Brucellosis is a common zoonotic disease throughout the world. Brucella spp. transmit to humans through contact with fluids of infected animals, especially sheep, cattle, and goats. It is also transmitted by ingestion of fluid-derived products of infected animals, such as unpasteurized milk and cheese. Brucella spp. changes pH level of intracellular environment, so the first treatment approach is to administer antibiotics that have activity in acidic conditions. Anti-brucellosis treatment regimens include doxycycline for children older than eight years old and rifampicin and trimethoprim/sulfamethoxazole (TMP-SMX) combination therapy for children under eight years old, which may be able to act intracellularly under acidic conditions. A TMP-SMX allergy causing anaphylaxis has been reported previously. No alternative anti-brucellosis treatments have been reported in the literature for patients under eight years old with a TMP-SMX allergy. Here, we report a case of a child with brucellosis and a TMP-SMX allergy who was under eight years old at the time of diagnosis and was successfully treated with rifampicin, ciprofloxacin, and gentamicin.

An evidence-based approach for providing cautionary recommendations to sulfonamide-allergic patients and determining cross-reactivity among sulfonamide-containing medications

WHAT IS KNOWN AND OBJECTIVE

Prescribing sulfonamide-containing medications for patients with sulfonamide allergy continues to complicate medical decisions. We examined the cautionary recommendations in the approved drug monographs and primary literature, and formulated an evidence-based grading of cautionary recommendations for sulfonamide allergy and cross-reactivity among sulfonamide-containing medications.

METHODS

Drug monographs were collected from six countries and three drug compendia. Two reviewers independently extracted the data from the contraindication, warning and/or precaution sections of drug monographs. Evidence for cross-reactivity was examined in the primary literature and compared with drug monograph recommendations. Consequently, medications were categorized based on the strength of recommendation and level of evidence by consensus.

RESULTS AND DISCUSSION

We identified wide variability in cautionary recommendations ranging from no warning or precaution to contraindication among the sources reviewed. The recommendations were located mainly in the contraindication section of monographs for France (65·2%), United Kingdom (51·9%), Italy (50·0%), South Korea (43·5%), United States (38·2%) and Canada (37·0%), whereas in drug compendia, the recommendations were found in the precaution section for Martindale (51·4%) and Micromedex-Drugdex (33·3%), and contraindication and precaution section for the American Hospital Formulary Service Drug Information 2010 (30·8%). Evidence from the primary literature varied with recommendation included in drug monographs. Evidence-based categorization was carried out for 16 medications. Two sulfonamide-moiety-containing drugs were considered safe, six non-sulfonylarylamines required precaution, and eight medications from all three sulfonamide chemical classes were considered mostly unsafe.

WHAT IS NEW AND CONCLUSION

There are significant discrepancies in cautionary recommendations included in drug-labels and drug compendia. Statements concerning cross-reactive hypersensitivity with other sulfonamides generally suggest theoretical possibilities. The consensus evidence-based grading instrument developed may be useful for deriving cautionary recommendations for sulfonamide-allergic patients.

Acetazolamide and sulfonamide allergy: a not so simple story

Allergies and adverse reactions to sulfonamide medications are quite common. Two distinct categories of drugs are classified as sulfonamides: antibiotics and nonantibiotics. The two groups differ in their chemical structure, use, and the rate at which adverse reactions occur. Cross-reactivity between the two groups has been implied in the past, but is suspect. Acetazolamide, from the nonantibiotic group, is routinely used in the prevention and treatment of high altitude issues and may not need to be avoided in individuals with a history of sulfonamide allergy. This review addresses the differences between the groups and the propensity for intergroup and intragroup adverse reactions based on the available literature. We also examine the different clinical presentations of allergy and adverse reactions, from simple cutaneous reactions with no sequelae through Stevens-Johnson syndrome and anaphylaxis, with risk for significant morbidity and mortality. We offer a systematic approach to determine whether acetazolamide is a safe option for those with a history of allergy to sulfonamides.

Sulfonamide antibiotics embedded in high silica zeolite Y: a combined experimental and theoretical study of host-guest and guest-guest interactions

A combined experimental and computational study of the interactions of three sulfonamides--sulfadiazine, sulfamethazine, and sulfachloropyridazine--embedded into the cages of high silica zeolite Y is here proposed. For all host-guest systems, the close vicinity of aromatic rings with zeolite framework was evidenced by multidimensional and multinuclear ((1)H, (13)C, (29)Si) SS-NMR measurements. Host-guest and guest-guest interactions were also elucidated by in situ FTIR spectroscopy and confirmed by ab initio computational modeling. Single molecules of sulfamethazine and sulfachloropyridazine were stabilized inside the zeolite cage by the vicinity of methyl and amino groups, respectively. Sulfadiazine is present in both monomeric and dimeric forms. Multiple weak H-bonds and van der Waals type interactions between organic molecules and zeolite are responsible for the irreversible extraction from water of all the examined sulfa drugs.

Severe allergic reaction to hydrochlorothiazide mimicking septic shock

Hydrochlorothiazide (HCTZ) is a sulfonamide-containing drug with commonly reported adverse effects that include electrolyte abnormalities, orthostatic hypotension, hyperglycemia, and photosensitivity. A few reports have described rare but serious drug complications such as interstitial pneumonitis, angioedema, and aplastic anemia. We describe a patient who experienced a serious HCTZ-induced adverse event that, to our knowledge, has not yet been reported in the literature. A 78-year-old woman came to the emergency department with dyspnea and severe fatigue; her signs and symptoms were suggestive of septic shock from pneumonia. She was treated accordingly, her condition improved, and she was discharged home. During the next 2 months, the patient returned to the emergency department 2 more times and was hospitalized each time with the same diagnosis. During her third admission, it was discovered that the patient's primary care physician had restarted her HCTZ for hypertension after it had been discontinued during each of the first two hospitalizations. The patient's symptoms began within hours of the first and second hospitalizations and almost immediately after taking a dose of HCTZ on the day of the third hospitalization. Her medical history revealed documented allergic reactions to sulfonamide drugs and penicillin; thus a hypersensitivity reaction to HCTZ was suspected. Use of the Naranjo adverse drug reaction probability scale indicated a probable relationship between the patient's hypersensitivity reactions and HCTZ therapy. Because of a lack of evidence showing cross-reactivity among the different classes of sulfonamides, the mechanism of the allergic reaction to HCTZ was unlikely to be cross-sensitivity between sulfonamide antibiotics and sulfonamide nonantibiotic drugs. Although the mechanism is not clear, evidence shows that the allergy to the HCTZ (sulfonamide nonantibiotic) may be due to a predisposition to drug allergies rather than sulfonamide cross-sensitivity. Clinicians should be aware of the potential for these types of allergic reactions.

Antibiotic allergies in the medical record: effect on drug selection and assessment of validity

STUDY OBJECTIVES

To determine the frequency with which reported antibiotic allergies alter drug selection and to assess the validity of these allergies.

DESIGN

Retrospective medical record review, with concurrent interviews conducted in a selected subgroup of patients.

SETTING

Tertiary care academic medical center.

PATIENTS

Three hundred patients with at least one documented antibiotic allergy and who received an antibiotic while hospitalized.

MEASUREMENTS AND MAIN RESULTS

Data were collected to determine the patients' allergies documented in the medical record. The first antibiotic regimen that each patient received while hospitalized was evaluated for deviation from the standard of care as determined from institutional protocols, recommendations in the literature, and expert opinion. A total of 416 allergies to antibiotics were reported. Penicillins were the agents most commonly reported (198 reports), followed by sulfonamides, cephalosporins, macrolides, and fluoroquinolones. The reported allergies altered antibiotic therapy in 91 (30.3%) patients. Report of a penicillin or cephalosporin allergy and use of antibiotics for prophylaxis were strong predictors of altered therapy. The subgroup consisted of 100 patients who were interviewed to determine the specific details of their reported allergic reactions. For 22 of the 100 patients, major discrepancies were found between their verbal reports and medical record documentation. The Naranjo adverse drug reaction probability scale was used to determine the validity of their reactions. Among these 100 patients, 109 (78.4%) of 139 reported reactions to antibiotics were deemed to be allergic in nature. For 55 (50.5%) of the 109 allergic reactions, the Naranjo score was 5 or greater, which correlates with probable to definite validity.

CONCLUSION

Discrepancies between the medical record and in-depth allergy histories are common, and the validity of reported allergic reactions is frequently questionable. Because documentation of an antibiotic allergy frequently alters therapy, increased effort to verify these reactions may be beneficial.

Allergies to sulfonamide antibiotics and sulfur-containing drugs

OBJECTIVE

To provide a literature review and clinical summary of the evaluation and management of sulfonamide drug reactions.

DATA SOURCES

Published English-language medical literature.

STUDY SELECTION

Selected trials of drug desensitization protocols.

RESULTS

Obtaining a detailed history is invaluable in assessing a history of reactions to sulfonamide medications, because allergy to these drugs remains a clinical diagnosis at present. Numerous efficacious drug desensitization protocols for management have been published and are reviewed in detail.

CONCLUSIONS

The term sulfa allergy is imprecise and misleading and therefore should be discouraged. There are important distinctions between sulfonylarylamines (antimicrobial sulfonamides), nonarylamine (nonantimicrobial) sulfonamides, and sulfones, with regard to allergic and other adverse drug reactions. Most reactions to sulfonylarylamines probably result from multifactorial immunologic and toxic metabolic mechanisms, whereas less is known about the precise mechanisms of reactions to other sulfur-containing drugs.

Sulpha allergy in lupus patients: a clinical perspective

Abstract

Systemic lupus erythematosus is a chronic, relapsing autoimmune disease that can affect multiple organ systems. An increased prevalence of drug allergy has been reported in lupus patients compared with the general population. Using a cohort of 417 lupus patients, we found a history of sulpha allergy in 27.3% of patients. European-American lupus patients with sulpha allergy are about two times more likely to suffer from lymphopenia, two times more likely to have anti-Ro autoantibody, and four times less likely to have anti-nRNP antibodies compared with lupus patients without a reported sulpha allergy ( P = 0.0075, 0.025, and 0.032, respectively). In African-American lupus patients, a history of sulpha allergy was associated with over three times increased odds of developing pericarditis ( P = 0.005).

Anaphylactic and anaphylactoid causes of angioedema

Anaphylactic and anaphylactoid (pseudoallergic) reactions can be expected to occur with greater frequency as the number of immunomodulators are employed. The immune system will become sensitized to these new therapeutic agents or there may be first-dose reactions depending on the pathogenetic mechanism involved. Physicians should review their office or procedure room emergency preparedness protocols and medications. The lack of penicillin major and minor determinants for penicillin testing has made management of penicillin and cephalosporin allergic patients more complicated. In the absence of skin-testing materials, test-challenges will be necessary and performed with less comfort because of not knowing the current level of immunologic sensitization to penicillin. The indication for readministration of any incriminated medication/therapeutic agent should be reviewed. Often, there are not suitable alternatives. Various approaches have been presented to permit safer readministration of essential medications or diagnostic agents to prevent episodes of anaphylaxis or upper airway angioedema.

Desensitization therapy in a patient with furosemide allergy

Allergy to furosemide is a rare phenomenon. Desensitization to this sulfa-containing drug has not been frequently performed. We describe a patient with severe congestive heart failure and type I allergy to furosemide. Because of the severity of her condition, we decided to use a rapid intravenous desensitization protocol. Following the desensitization, the patient was treated with intravenous and oral furosemide with a dramatic improvement in her clinical state. We suggest that rapid desensitization may be a safe and effective way of introducing furosemide to allergic patients for whom loop diuretics are urgently indicated.

Hydrochlorothiazide-induced angioedema in a patient allergic to sulfonamide antibiotics: Evidence from a case report and a review of the literature

BACKGROUND

Hypersensitivity reactions in patients receiving sulfonamide antibiotics have been frequently documented in the literature, but cross-reactivity with sulfonamide non-antibiotics rarely has been reported.

CASE SUMMARY

An 82-year-old woman with a history of hypersensitivity reactions to sulfamethoxazole-trimethoprim resulting in angioedema and rash presented to the emergency department (ED) with angioedema and severe dysphagia, shortness of breath, and rash after receiving valsartan and hydrochlorothiazide (HCTZ) for 4 months. Valsartan was identified as the most likely cause of the symptoms and was discontinued; however, the patient continued to have weekly episodes of angioedema and eventually returned to the ED. HCTZ was discontinued at the second ED visit, and the angioedema disappeared. However, it reappeared after reinitiation of HCTZ, and the patient returned to the ED again; this time with more severe symptoms. After the third ED visit and second hospitalization, HCTZ was permanently discontinued, and the angioedema has not returned. HCTZ was the definite cause of angioedema in this patient based on a score of 9 on the 10-point Naranjo adverse drug reaction probability scale.

CONCLUSIONS

Although the probability of true cross-reactivity is not known, clinicians should be aware that an allergic-like reaction to sulfonamide-containing non-antibiotics may occur in patients with known allergies to sulfonamide-containing antibiotics. These patients should be monitored closely when receiving these drugs. Further evaluation is needed to determine whether angioedema should be added to the list of adverse events associated with HCTZ.