Leukotriene receptor antagonists as add-on therapy to antihistamines for urticaria: Systematic review and meta-analysis of randomized clinical trials.

BACKGROUND: The benefits and harms of adding antileukotrienes to H1 antihistamines (AHs) for the management of urticaria (hives, itch, and/or angioedema) remain unclear. OBJECTIVE: We sought to systematically synthesize the treatment outcomes of antileukotrienes in combination with AHs versus AHs alone for acute and chronic urticaria. METHODS: As part of updating American Academy of Allergy, Asthma & Immunology and American College of Allergy, Asthma, and Immunology Joint Task Force on Practice Parameters urticaria guidelines, we searched Medline, Embase, Central, LILACS, WPRIM, IBECS, ICTRP, CBM, CNKI, VIP, Wanfang, US Food and Drug Administration, and European Medicines Agency databases from inception to December 18, 2023, for randomized controlled trials (RCTs) evaluating antileukotrienes and AHs versus AHs alone in patients with urticaria. Paired reviewers independently screened citations, extracted data, and assessed risk of bias. Random effects models pooled effect estimates for urticaria activity, itch, wheal, sleep, quality of life, and harms. The GRADE approach informed certainty of evidence ratings. The study was registered at the Open Science Framework (osf.io/h2bfx/). RESULTS: Thirty-four RCTs enrolled 3324 children and adults. Compared to AHs alone, the combination of a leukotriene receptor antagonist with AHs probably modestly reduces urticaria activity (mean difference, -5.04; 95% confidence interval, -6.36 to -3.71; 7-day urticaria activity score) with moderate certainty. We made similar findings for itch and wheal severity as well as quality of life. Adverse events were probably not different between groups (moderate certainty); however, no RCT reported on neuropsychiatric adverse events. CONCLUSION: Among patients with urticaria, adding leukotriene receptor antagonists to AHs probably modestly improves urticaria activity with little to no increase in overall adverse events. The added risk of neuropsychiatric adverse events in this population with leukotriene receptor antagonists is small and uncertain.

Topical corticosteroids for hives and itch (urticaria): systematic review and Bayesian meta-analysis of randomized trials.

BACKGROUND: Topical corticosteroids are widely used as a treatment for itch and wheals (urticaria), but their benefits and harms are unclear. OBJECTIVE: To systematically synthesize the benefits and harms of topical corticosteroids for the treatment of urticaria. METHODS: We searched MEDLINE, EMBASE, and CENTRAL from database inception to March 23, 2024, for randomized trials addressing comparing topical corticosteroid to placebo for patients with urticaria (either chronic spontaneous or inducible urticaria or acute urticaria elicited from skin/intradermal allergy testing). Paired reviewers independently screened records, extracted data, and assessed risk of bias. Random-effects meta-analyses addressed urticaria severity, itch severity (numeric rating scale; range 0-10; higher is worse), and adverse events. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach informed certainty of evidence ratings. PROSPERO registration: CRD42023455182. RESULTS: Nineteen RCTs enrolled 379 participants with a median of mean age of 30.1 years (range 21.1 to 44.0). Compared to placebo, topical corticosteroids may reduce wheal size (ratio of means 0.47, 95%CI 0.38 to 0.59; low certainty) and itch severity (mean difference -1.30, 95%CI -5.07 to 2.46; very low certainty). Topical corticosteroids result in little to no difference in overall adverse events (94 fewer patients per 1000, 95%CrI 172 fewer to 12 more; high certainty). CONCLUSION: Compared to placebo, topical corticosteroids may result in a reduction of wheal size, and result in little to no difference in overall adverse events. Topical corticosteroids may reduce itch severity, but the evidence is very uncertain. Future large, randomized trials addressing the use of topical corticosteroids would further support optimal urticaria management.

Efficacy and Safety of Systemic Corticosteroids for Urticaria: A Systematic Review and Meta-Analysis of Randomized Clinical Trials.

BACKGROUND: Short courses of adjunctive systemic corticosteroids are commonly used to treat acute urticaria and chronic urticaria flares (both with and without mast cell-mediated angioedema), but their benefits and harms are unclear. OBJECTIVE: To evaluate the efficacy and safety of treating acute urticaria or chronic urticaria flares with versus without systemic corticosteroids. METHODS: We searched the MEDLINE, EMBASE, CENTRAL, CNKI, VIP, Wanfang, and CBM databases from inception to July 8, 2023, for randomized controlled trials of treating urticaria with versus without systemic corticosteroids. Paired reviewers independently screened records, extracted data, and appraised risk of bias with the Cochrane 2.0 tool. We performed random-effects meta-analyses of urticaria activity, itch severity, and adverse events. We assessed certainty of the evidence using the Grading of Recommendations Assessment, Development and Evaluations (GRADE) approach. RESULTS: We identified 12 randomized trials enrolling 944 patients. For patients with low or moderate probability (17.5%-64%) to improve with antihistamines alone, add-on systemic corticosteroids likely improve urticaria activity by a 14% to 15% absolute difference (odds ratio [OR], 2.17, 95% confidence interval [CI]: 1.43-3.31; number needed to treat [NNT], 7; moderate certainty). Among patients with a high chance (95.8%) for urticaria to improve with antihistamines alone, add-on systemic corticosteroids likely improved urticaria activity by a 2.2% absolute difference (NNT, 45; moderate certainty). Corticosteroids may improve itch severity (OR, 2.44; 95% CI: 0.87-6.83; risk difference, 9%; NNT, 11; low certainty). Systemic corticosteroids also likely increase adverse events (OR, 2.76; 95% CI: 1.00-7.62; risk difference, 15%; number needed to harm, 9; moderate certainty). CONCLUSIONS: Systemic corticosteroids for acute urticaria or chronic urticaria exacerbations likely improve urticaria, depending on antihistamine responsiveness, but also likely increase adverse effects in approximately 15% more.

Clinical severity classes in COVID-19 pneumonia have distinct immunological profiles, facilitating risk stratification by machine learning.

Objective: Clinical triage in coronavirus disease 2019 (COVID-19) places a heavy burden on senior clinicians during a pandemic situation. However, risk stratification based on serum biomarker bioprofiling could be implemented by a larger, nonspecialist workforce. Method: Measures of Complement Activation and inflammation in patientS with CoronAvirus DisEase 2019 (CASCADE) patients (n = 72), (clinicaltrials.gov: NCT04453527), classified as mild, moderate, or severe (by support needed to maintain SpO2 > 93%), and healthy controls (HC, n = 20), were bioprofiled using 76 immunological biomarkers and compared using ANOVA. Spearman correlation analysis on biomarker pairs was visualised via heatmaps. Linear Discriminant Analysis (LDA) models were generated to identify patients likely to deteriorate. An X-Gradient-boost (XGB) model trained on CASCADE data to triage patients as mild, moderate, and severe was retrospectively employed to classify COROnavirus Nomacopan Emergency Treatment for covid 19 infected patients with early signs of respiratory distress (CORONET) patients (n = 7) treated with nomacopan. Results: The LDA models distinctly discriminated between deteriorators, nondeteriorators, and HC, with IL-27, IP-10, MDC, ferritin, C5, and sC5b-9 among the key predictor variables during deterioration. C3a and C5 were elevated in all severity classes vs. HC (p < 0.05). sC5b-9 was elevated in the "moderate" and "severe" categories vs. HC (p < 0.001). Heatmap analysis shows a pairwise increase of negatively correlated pairs with IL-27. The XGB model indicated sC5b-9, IL-8, MCP1, and prothrombin F1 and F2 were key discriminators in nomacopan-treated patients (CORONET study). Conclusion: Distinct immunological fingerprints from serum biomarkers exist within different severity classes of COVID-19, and harnessing them using machine learning enabled the development of clinically useful triage and prognostic tools. Complement-mediated lung injury plays a key role in COVID-19 pneumonia, and preliminary results hint at the usefulness of a C5 inhibitor in COVID-19 recovery.

Hereditary Angioedema.

Hereditary angioedema (HAE) is a rare autosomal dominant genetic disorder that usual results from a decreased level of functional C1-INH and clinically manifests with intermittent attacks of swelling of the subcutaneous tissue or submucosal layers of the respiratory or gastrointestinal tracts. Laboratory studies and radiographic imaging have limited roles in evaluation of patients with acute attacks of HAE except when the diagnosis is uncertain and other processes must be ruled out. Treatment begins with assessment of the airway to determine the need for immediate intervention. Emergency physicians should understand the pathophysiology of HAE to help guide management decisions.

The Role of Cetirizine in the Changing Landscape of IV Antihistamines: A Narrative Review.

Since 1955, the only available H1 antihistamines for intravenous administration have been first-generation formulations and, of those, only intravenously administered (IV) diphenhydramine is still approved in the USA. Orally administered cetirizine hydrochloride, a second-generation H1 antihistamine, has been safely used over-the-counter for many years. In 2019, IV cetirizine was approved for the treatment of acute urticaria. In light of this approval, this narrative review discusses the changing landscape of IV antihistamines for the treatment of histamine-mediated conditions. Specifically, IV antihistamines will be discussed as a treatment option for acute urticaria and angioedema, as premedication to prevent infusion reactions related to anticancer agents and other biologics, and as an adjunct treatment for anaphylaxis and other allergic reactions. Before the development of IV cetirizine, randomized controlled trials of IV antihistamines for these indications were lacking. Three randomized controlled trials have been conducted with IV cetirizine versus IV diphenhydramine in the ambulatory care setting. A phase 3 trial of IV cetirizine 10 mg versus IV diphenhydramine 50 mg was conducted in 262 adults who presented to the urgent care/emergency department with acute urticaria requiring antihistamines. For the primary efficacy endpoint, defined as change from baseline in a 2-h patient-rated pruritus score, non-inferiority of IV cetirizine to IV diphenhydramine was demonstrated (score - 1.6 vs - 1.5, respectively; 95% CI - 0.1, 0.3). Compared with IV diphenhydramine, IV cetirizine demonstrated fewer adverse effects including less sedation, a significantly shorter length of stay in the treatment center, and fewer returns to the treatment center at 24 and 48 h. Similar findings were demonstrated in another phase 2 acute urticaria trial and in a phase 2 trial assessing IV cetirizine for pretreatment for infusion reactions in the oncology/immunology setting. IV cetirizine is associated with similar patient outcomes, fewer adverse effects, and increased treatment center efficiency than IV diphenhydramine.

Hereditary Angioedema.

Hereditary angioedema (HAE) is a rare autosomal dominant genetic disorder that usual results from a decreased level of functional C1-INH and clinically manifests with intermittent attacks of swelling of the subcutaneous tissue or submucosal layers of the respiratory or gastrointestinal tracts. Laboratory studies and radiographic imaging have limited roles in evaluation of patients with acute attacks of HAE except when the diagnosis is uncertain and other processes must be ruled out. Treatment begins with assessment of the airway to determine the need for immediate intervention. Emergency physicians should understand the pathophysiology of HAE to help guide management decisions.

Intravenous Cetirizine Versus Intravenous Diphenhydramine for the Treatment of Acute Urticaria: A Phase III Randomized Controlled Noninferiority Trial.

STUDY OBJECTIVE: Acute urticaria is a frequent presentation in emergency departments (EDs), urgent care centers, and other clinical arenas. Treatment options are limited if diphenhydramine is the only intravenous antihistamine offered because of its short duration of action and well-known adverse effects. We evaluate cetirizine injection, the first second-generation injectable antihistamine, for acute urticaria in this multicenter, randomized, noninferiority, phase 3 clinical trial. METHODS: Adult patients presenting to EDs and urgent care centers with acute urticaria requiring an intravenous antihistamine were randomized to either intravenous cetirizine 10 mg or intravenous diphenhydramine 50 mg. The primary endpoint was the 2-hour pruritus score change from baseline, with time spent in treatment center and rate of return to treatment centers as key secondary endpoints. Frequency of sedation and anticholinergic adverse effects were also recorded. RESULTS: Among 262 enrolled patients, the 2-hour pruritus score change from baseline for intravenous cetirizine was statistically noninferior to that for intravenous diphenhydramine (-1.6 versus -1.5; 95% confidence interval -0.1 to 0.3), and in favor of cetirizine. Treatment differences also favored cetirizine for mean time spent in treatment center (1.7 versus 2.1 hours; P=.005), return to treatment center (5.5% versus 14.1%; P=.02), lower change from baseline sedation score at 2 hours (0.1 versus 0.5; P=.03), and adverse event rate (3.9% versus 13.3%). CONCLUSION: Intravenous cetirizine is an effective alternative to intravenous diphenhydramine for treating acute urticaria, with benefits of less sedation, fewer adverse events, shorter time spent in treatment center, and lower rates of revisit to treatment center.

Emergency department evaluation of patients with angiotensin converting enzyme inhibitor associated angioedema.

INTRODUCTION: Angiotensin converting enzyme inhibitor (ACEi) associated angioedema is frequently encountered in the emergency department. Airway management is the primary treatment, but published evidence supporting the decision to intubate patients with this condition is extremely limited. METHOD: We performed a retrospective study of all cases of ACEi associated angioedema encountered in a large, urban, tertiary referral emergency department. We classified demographics, duration of symptoms before presentation, physical exam findings and nasopharyngoscopy findings in patients that did and did not require intubation. RESULTS: We identified a total of 190 separate encounters from 183 unique patients who presented during the 3-year period of the study. Eighteen (9.5%) of these patients required intubation. Patients requiring intubation were more likely to present within 6 h of the onset of angioedema symptoms. Anterior tongue swelling, vocal changes, drooling, and dyspnea were significantly more common in patients requiring intubation. Isolated lip swelling was present in 54% of all patients and was the only finding significantly more common in the group that did not require intubation. CONCLUSIONS: Rapid progression of symptoms within the first 6 h of angioedema onset, anterior tongue swelling, vocal changes, drooling and dyspnea are associated with intubation for ACEi associated angioedema. Isolated lip swelling is significantly more common in patients that do not require intubation. Our data provide risk stratification guidance for providers treating patients with suspected ACEi associated angioedema in the emergency department.

Development and validation of the angiotensin-converting enzyme inhibitor (ACEI) induced angioedema investigator rating scale and proposed discharge criteria.

BACKGROUND: The use of angiotensin-converting enzyme inhibitors (ACEI) has been associated with the development of bradykinin-mediated angioedema. With ever-widening indications for ACEI in diseases including hypertension, congestive heart failure and diabetic nephropathy, a concomitant increase in ACEI-Angioedema (ACEI-A) has been reported. At present there is no validated severity scoring or discharge criteria for ACEI-A. We sought to develop and validate an investigator rating scale with corresponding discharge criteria using clinicians experienced in treating ACEI-A. METHODS: In-depth, 60-min qualitative telephone interviews were conducted with 12 US-based emergency physicians. Beforehand, clinicians were sent four case studies describing patients experiencing different severities of angioedema attacks. Clinicians were initially asked open-ended questions about their experience of patients' symptoms, treatment and discharge decisions. Clinicians then rated each patient case study and discussed patient diagnoses, ratings of symptom severity and discharge evaluation. The ratings were used to assess inter-rater reliability of the scale using the intra-class correlation coefficient (ICC) using IBM SPSS analysis Version 19 software. RESULTS: The findings provide support focusing on four key symptoms of airway compromise scored on a 0-4 scale: 1) Difficulty Breathing, 2) Difficulty Swallowing, 3) Voice Changes and 4) Tongue Swelling and the corresponding discharge criteria of a score of 0 or 'No symptoms' for Difficulty Breathing and Difficulty Swallowing and a score of 0 or 1 indicating mild or absence of symptoms for Voice Change and Tongue Swelling. Eleven clinicians agreed the absence of standardized discharge criteria supported the use of this scale. All physicians concurred with the recommended discharge criteria. The clinician ratings provided evidence of strong inter-rater reliability for the rating scale (ICC > 0.80). CONCLUSION: The investigator rating scale and discharge criteria are clinically valid, relevant and reliable. Moreover, both address the current unmet need for standardized ED discharge criteria.

Randomized Trial of Icatibant for Angiotensin-Converting Enzyme Inhibitor-Induced Upper Airway Angioedema.

BACKGROUND: Upper airway angioedema is a rare, unpredictable, and at times life-threatening adverse effect of angiotensin-converting enzyme inhibitors (ACE-Is) with no existing effective pharmacologic treatment. Icatibant is a bradykinin B2 receptor antagonist that may be beneficial in patients with ACE-I-induced angioedema. OBJECTIVE: We aimed to evaluate the efficacy of icatibant in subjects with ACE-I-induced angioedema. METHODS: At 31 centers in 4 countries, adults on ACE-Is who presented within 12 hours of the onset of at least moderately severe angioedema were randomized 1:1 to icatibant 30 mg or placebo administered subcutaneously. The primary efficacy end point was time to meeting discharge criteria after study drug administration, based on the severity of airway symptoms assessed hourly by a blinded physician using clinical ratings across 4 domains. RESULTS: A total of 121 subjects were randomized (icatibant, n = 61; placebo, n = 60); 118 received treatment a median of 7.8 hours from symptom onset. We observed no difference in time to meeting discharge criteria between groups (median, 4.0 hours in each group; P = .63). There also was no difference in time to onset of symptom relief (median, icatibant, 2.0 hours; placebo, 1.6 hours; P = .57) or any other secondary end point. Similar findings were noted in prespecified and post hoc subgroup analyses stratified by symptom severity, time interval to treatment, age, and other clinical covariates. No new safety signals were detected. CONCLUSIONS: Icatibant was no more efficacious than placebo in at least moderately severe ACE-I-induced angioedema of the upper airway.

Effectiveness of ecallantide in treating angiotensin-converting enzyme inhibitor-induced angioedema in the emergency department.

BACKGROUND: Angiotensin-converting enzyme inhibitor-induced angioedema (ACEI-AE) is mediated by bradykinin. There remains an unmet treatment need because these patients, when presenting to the emergency department (ED), do not respond to conventional therapies, such as antihistamines and corticosteroids. OBJECTIVE: To estimate the treatment effect of ecallantide, a recombinant plasma kallikrein inhibitor, in ED patients with ACEI-AE in whom conventional therapy fails. METHODS: This was a triple-blind (patient, physician, and statistician), randomized, controlled, phase 2 study to estimate the magnitude of safety and efficacy signals for designing a definitive phase 3 trial comparing conventional therapy with ecallantide to conventional therapy with placebo. Patients were enrolled from April 1, 2010, through January 31, 2013. The primary efficacy study end point was achieving discharge criteria from the ED within 4 hours after initiating study-related treatment. RESULTS: Discharge criteria from the ED was met in 4 hours or less for 8 (31%) of 26 patients receiving ecallantide vs 5 of (21%) 24 patients receiving placebo (difference in proportions, 10%; 95% confidence interval, -14% to 34%). Ecallantide was well tolerated in both groups. CONCLUSION: The results from this preliminary study reveal that ecallantide is safe to use and may increase the proportion of patients who meet early discharge criteria by approximately10%. A larger phase 3 study is necessary to confirm the efficacy and evaluate the cost-effectiveness of ecallantide use for ACEI-AE in the ED setting. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01036659.

A consensus parameter for the evaluation and management of angioedema in the emergency department.

Despite its relatively common occurrence and life-threatening potential, the management of angioedema in the emergency department (ED) is lacking in terms of a structured approach. It is paramount to distinguish the different etiologies of angioedema from one another and more specifically differentiate histaminergic-mediated angioedema from bradykinin-mediated angioedema, especially in lieu of the more novel treatments that have recently become available for bradykinin-mediated angioedema. With this background in mind, this consensus parameter for the evaluation and management of angioedema attempts to provide a working framework for emergency physicians (EPs) in approaching the patient with angioedema in terms of diagnosis and management in the ED. This consensus parameter was developed from a collaborative effort among a group of EPs and leading allergists with expertise in angioedema. After rigorous debate, review of the literature, and expert opinion, the following consensus guideline document was created. The document has been endorsed by the American College of Allergy, Asthma & Immunology (ACAAI) and the Society for Academic Emergency Medicine (SAEM).

Factors associated with hospitalization of patients with angiotensin-converting enzyme inhibitor-induced angioedema.

Angiotensin-converting enzyme inhibitor (ACE-I)-induced angioedema can be life-threatening without emergent intervention. The putative mediator is believed to be bradykinin, similar to hereditary angioedema, so these patients respond poorly to corticosteroids and antihistamines. This study was designed to determine characteristics and clinical outcomes of patients presenting to an emergency department (ED) with ACE-I angioedema. This was a retrospective chart review of 100 patients presenting to the ED from 2007 to 2008 with an ICD-9 code of 995.1 (angioedema) or 995.2 (drug-induced angioedema). Two hundred fifty-two patients with these ICD-9 codes were identified and placed in random order, and the first 100 meeting inclusion criteria were included. Statistical analysis was primarily descriptive. All 100 patients had an ICD-9 code of 995.1 (angioedema). Patients presented in every month, with spring months (April-June) having the most presentations (32%). The median age was 59 years, 75% were African American, and 66% were admitted to the hospital. Two patients (2%) required endotracheal intubation. Lisinopril was the most commonly prescribed ACE-I (84%). The most common symptom was moderate lip and tongue swelling (89%) followed by mild difficulty breathing (12%). Tongue swelling was significantly associated with admission. Time from symptom onset to ED presentation was not associated with need for admission. Concomitant medications did not differ between admitted and discharged patients. ACE-I angioedema is associated with significant morbidity and health care use because many patients require hospitalization, suggesting an unmet need for novel therapies targeted to treat this condition.

Emerging concepts in the diagnosis and treatment of patients with undifferentiated angioedema.

Angioedema is a sudden, transient swelling of well-demarcated areas of the dermis, subcutaneous tissue, mucosa, and submucosal tissues that can occur with or without urticaria. Up to 25% of people in the US will experience an episode of urticaria or angioedema during their lifetime, and many will present to the emergency department with an acute attack. Most cases of angioedema are attributable to the vasoactive mediators histamine and bradykinin. Histamine-mediated (allergic) angioedema occurs through a type I hypersensitivity reaction, whereas bradykinin-mediated (non-allergic) angioedema is iatrogenic or hereditary in origin.Although their clinical presentations bear similarities, the treatment algorithm for histamine-mediated angioedema differs significantly from that for bradykinin-mediated angioedema. Corticosteroids, and epinephrine are effective in the management of histamine-mediated angioedema but are ineffective in the management of bradykinin-mediated angioedema. Recent advancements in the understanding of angioedema have yielded pharmacologic treatment options for hereditary angioedema, a rare hereditary form of bradykinin-mediated angioedema. These novel therapies include a kallikrein inhibitor (ecallantide) and a bradykinin ß2 receptor antagonist (icatibant). The physician's ability to distinguish between these types of angioedema is critical in optimizing outcomes in the acute care setting with appropriate treatment. This article reviews the pathophysiologic mechanisms, clinical presentations, and diagnostic laboratory evaluation of angioedema, along with acute management strategies for attacks.

Progress in the emergency management of hereditary angioedema: focus on new treatment options in the United States.

Hereditary angioedema (HAE) is a rare disorder generally caused by a deficit in the activity of C1-esterase inhibitor (C1-INH). Symptoms manifest as recurrent episodes of nonallergic, nonpruritic, and nonpitting edema. Attacks commonly occur on the extremities, trunk, genitalia, abdomen, or head and neck--the latter 2 locations are associated with the greatest morbidity and mortality. In the United States, there has been a considerable void in effective HAE treatments and emergency management guidelines. Clinical outcomes using agents such as fresh-frozen plasma, attenuated androgens (danazol), or plasmin inhibitors (aminocaproic acid) have not been ideal. Recent years have seen progress with US Food and Drug Administration (FDA) approval of several products for acute HAE treatment. Plasma concentrate of C1-INH has long been the treatment of choice in many parts of the world, and a pasteurized formula received FDA approval in October 2009 for treating attacks. Ecallantide, a plasma kallikrein inhibitor, and icatibant, a bradykinin receptor antagonist, were approved in December 2009 and August 2011, respectively, for treatment of acute attacks. A recombinant C1-INH product is in late development stages for treating acute attacks. These new treatments provide symptom relief within hours, dramatically shorten attack duration, and decrease mortality from airway compromise. For the first time, US physicians have rapid-acting and highly effective treatments for managing acute HAE attacks.

Diagnosis and management of hereditary angioedema: an emergency medicine perspective.

BACKGROUND: Hereditary angioedema (HAE) is a rare and often debilitating condition associated with substantial morbidity and mortality in the absence of appropriate intervention. An underlying deficiency in functional C1-inhibitor (C1-INH) protein induces a vulnerability to unchecked activation of the complement, contact, and coagulation/fibrinolytic systems. The clinical consequence is a pattern of recurring attacks of non-pitting, non-pruritic edema, the urgency of which varies by the affected site. Laryngeal edema can escalate rapidly to asphyxiation, and severe cases of abdominal swelling can lead to hypovolemic shock. OBJECTIVES: This report reviews the emergency diagnosis and treatment of hereditary angioedema and the impact of recently introduced treatments on treatment in the United States. DISCUSSION: Until recently, emergency physicians in the United States were hindered by the lack of rapidly effective treatment options for HAE attacks. In this article, general clinical and laboratory diagnostic procedures are reviewed against the backdrop of two case studies: one patient presenting with a known history of HAE and one with previously undiagnosed HAE. In many countries outside the United States, plasma-derived C1-INH concentrate has for decades been the first-line treatment for acute attacks. The end of 2009 ushered in a new era in the pharmacologic management of HAE attacks in the United States with the approval of two new treatment options for acute treatment: a plasma-derived C1-INH concentrate and a kallikrein inhibitor. CONCLUSION: With access to targeted and effective treatments, emergency physicians are now better equipped for successful and rapid intervention in urgent HAE cases.

The use of penicillin skin testing to assess the prevalence of penicillin allergy in an emergency department setting.

STUDY OBJECTIVE: Patient-reported penicillin allergies are often unreliable and can result in unnecessary changes in antibiotic therapy. Although penicillin allergy skin testing is commonly performed in allergy clinics, it has not been used in emergency departments (EDs) to verify self-reported allergies. We hypothesize that ED-based testing is possible and that the false-positive rate of patients with self-reported penicillin allergy are greater than 90%. METHODS: This prospective observational cohort study enrolled a convenience sample of ED patients with a self-reported penicillin allergy. Patients were enrolled by one of 2 emergency physicians who performed skin prick and intracutaneous tests with penicillin major and minor determinants. The total testing time was 30 minutes. The proportion of false-positive self-reported allergies was computed with 95% confidence intervals (CIs) by using the score method. RESULTS: A total of 150 patients (mean age 42 years; SD 16 years; 46% men; 47% black) were enrolled. The false-positive rate for self-reported penicillin allergy was 137 of 150 (91.3%; 95% CI 85.3% to 95.1%). There were no adverse reactions associated with penicillin skin testing. Compared with patients with a false-positive penicillin allergy result (confirmed by negative penicillin skin testing result), patients reporting a true penicillin allergy confirmed by positive penicillin skin test results tended to be more frequently men (61.5% versus 44.5%; Delta 17.0%; 95% CI -13.5% to 42%), black (69.2% versus 44.5%; Delta 24.7%; 95% CI -6.9% to 46.8%), and have no family history of drug allergy (7.7% versus 17.5%; Delta9.8%; 95% CI -20.9% to 20.4%), but self-reported other drug allergies more frequently (61.5% versus 38.7%; Delta 22.9%; 95% CI -7.7% to 47.5%). CONCLUSION: Penicillin skin testing is feasible in the ED setting. A substantial number of patients who self-report a penicillin allergy do not exhibit immunoglobulin E-mediated sensitization to penicillin major and minor determinants. Penicillin testing in the ED may allow the use of more appropriate antibiotics for patients presenting with a history of penicillin allergy.