Paradoxical Worsening of Chronic Spontaneous Urticaria Following Omalizumab Administration: The Missing Link.

Omalizumab, a humanized anti-IgE monoclonal antibody, is commonly employed in the treatment of antihistamine-refractory chronic spontaneous urticaria (CSU), where it significantly reduces free IgE levels, minimizing histamine release from basophils and mast cells. Despite its efficacy, there are concerns regarding its effect on parasitic defense due to IgE's role in combating parasitic infestations. We present a case of a 28-year-old female agriculturist with a six-month history of CSU who experienced a paradoxical exacerbation of her symptoms following an increase in the omalizumab treatment dose. This deterioration coincided with a serologically confirmed parasitic infection with Echinococcus granulosus and Toxocara canis. Despite normal eosinophil counts and IgE levels, which are typically used to identify parasitic infections, the patient's clinical worsening prompted further investigation that led to the identification of the parasitic infection. Treatment with albendazole and omalizumab discontinuation led to the resolution of her CSU, suggesting that the parasitic infection was contributing to the symptom exacerbation. This case highlights the need for careful screening for parasitic infections before initiating omalizumab in antihistamine-refractory CSU patients from endemic regions, or patients who deteriorate clinically on omalizumab, especially when other indicators such as eosinophil count and IgE levels might not suggest infection. It also underscores the importance of considering a tailored approach to managing CSU that balances effective treatment with the potential for adverse effects related to immunomodulation.

Acute Motor Conduction Block Neuropathy After Initiation of Omalizumab: Case Report and Literature Review for Possible Causality.

Background: Omalizumab is an established therapy for allergic conditions, yet its neurological effects remain underexplored compared to other biological agents. Case description: A 45-year-old male with asthma developed acute quadriparesis one week after receiving the first dose of omalizumab. Electrophysiological studies have shown partial motor conduction block in multiple nerves, with reduced CMAP amplitudes and absent F-waves in others. CSF showed cyto-albuminous dissociation. The diagnosis was a variant of Guillain-Barré syndrome. Despite intravenous immunoglobulin (IVIG) therapy, the patient experienced persistent neuropathic symptoms. Discussion: The patient presented with acute quadriparesis devoid of sensory or cranial nerve involvement, suggestive of a variant of Guillain-Barré syndrome (GBS) known as acute motor conduction block neuropathy (AMCBN). Electrophysiological studies have indicated conduction block without demyelination, implicating axonal degeneration. Despite negative findings for common etiologies, the temporal association between omalizumab administration and symptom onset suggests a potential link, supported by criteria for drug-induced illness. Conflicting evidence exists regarding omalizumab's neurological effects, with proposed mechanisms including autoimmune reactions and mast cell dysfunction. Comparisons to TNF-α antagonists highlight similar neuropathy patterns, indicating a need for further research to clarify omalizumab's neurotoxicity. Conclusion: In conclusion, while omalizumab holds promise for allergic conditions, including chronic urticaria, its potential impact on peripheral nerves necessitates vigilance among clinicians. Further studies are imperative to ascertain the risk-benefit profile and elucidate underlying mechanisms and risk factors of neurological complications associated with omalizumab therapy.

Long-term use of omalizumab in patients with allergic bronchopulmonary aspergillosis: a tertiary-level care center experience.

INTRODUCTION: Allergic bronchopulmonary aspergillosis (ABPA) is a lung disease caused by a hypersensitivity reaction to antigens of Aspergillus fumigatus. OBJECTIVE: The aim of this study was to evaluate the long-term clinical outcomes of omalizumab use in patients with ABPA. METHODS: In this retrospective study, 12 patients diagnosed with ABPA and receiving omalizumab for at least 2 years, and 32 patients diagnosed with severe allergic asthma and receiving omalizumab for at least 2 years (control group) were evaluated. RESULTS: Evaluation was made of a total of 44 participants, comprising 11 (25%) males and 33 (75%) females, who received omalizumab for at least 2 years with the diagnosis of the control group (n = 32) and ABPA (n = 12). The increase in asthma control test (ACT) score after omalizumab was significant at 12 months and at 24 months in patients with ABPA. After omalizumab, the use of oral corticosteroid (OCS), the annual number of asthma attacks and hospitalizations were significantly decreased at 12 months and at 24 months in patients with ABPA. The increase in forced expiratory volume in 1 s (FEV1) (%) and ACT score after omalizumab were significant at 12 months and at 24 months in the control group. After omalizumab, the use of OCS, annual number of asthma attacks and hospitalizations were significantly decreased at 12 months and at 24 months in the control group. CONCLUSION: Long-term omalizumab use in patients with ABPA seems to be an effective treatment for improving pulmonary function and reducing asthma exacerbations and hospitalizations.

Favorable clinical course after discontinuation of omalizumab treatment in patients with allergic severe asthma: A real-world clinical practice.

The success rate of omalizumab discontinuation is 50-75.5%. However, such data are scarce in Japan. We retrospectively investigated the clinical progression following the cessation of long-term omalizumab treatment (>5 years) in severe allergic asthma patients who have achieved super-responder status, defined as being off any oral maintenance corticosteroids without experiencing exacerbations requiring systemic corticosteroids for >1 year. Six (28.6%) among 21 patients recommenced after a median period of 5.5 (4.3-12.5) months later due to exacerbated asthma control, resulting in improved asthma management for all patients. The rates of patients who successfully remained off omalizumab treatment for 1 and 2 years were 72.4% and 65.8%, respectively. Specific IgE levels after discontinuing omalizumab treatment significantly decreased compared to those at initiating this treatment in 10 patients who successfully remained off this treatment. Therefore, discontinuing omalizumab treatment may be considered for patients continuing treatment beyond 5 years and achieving super-responder status.

Time-course and dose-effect of omalizumab in treating chronic idiopathic urticaria/chronic spontaneous urticaria.

PURPOSE: Several studies have shown that subcutaneous injections of omalizumab can treat chronic idiopathic/spontaneous urticaria (CIU/CSU) patients by only assessing the efficacy on specific endpoints. This study aimed to quantitatively analyze different doses of omalizumab in CIU/CSU and compare it with ligelizumab. METHODS: Literature searches were performed in PubMed, Embase, and Web of Science databases. A model-based meta-analysis (MBMA) was utilized to develop a model incorporating time since the initiation of treatment and dose for omalizumab, with the change from baseline in Urticaria Activity Score (CFB-UAS7) as the primary efficacy endpoint. The time-course and dose-effect relationship throughout the omalizumab treatment period was analyzed, and the findings were compared with those of the investigational ligelizumab. RESULTS: The model equation for the CFB-UAS7 was established as E = -Emax × time/(ET50 + time) × (b0 + b1 × dose). The estimated values of the model parameters E max , ET 50 , b 0 , and b 1 were -1.16, 1.26 weeks, -9.90, and -0.0361 mg-1, respectively. At week 12 after the first dose, the model-predicted CFB-UAS7 for 150 mg and 300 mg of omalizumab were -16.0 (95% CI, -17.2 to -14.8) and -21.7 (95% CI, -22.9 to -20.5), respectively. In the PEARL-1 trial, the CFB-UAS7 for 72 mg and 120 mg of ligelizumab were -19.4 (95% CI, -20.7 to -18.1) and -19.3 (95% CI, -20.6 to -18.0), respectively. In the PEARL-2 trial, these values were -19.2 (95% CI, -20.5 to -17.9) and -20.3 (95% CI, -21.6 to -19.0), respectively. CONCLUSION: Omalizumab showed a significant dose-dependent effect in the treatment of CSU. Both 72 mg and 120 mg ligelizumab might have the potential to outperform 150 mg (but not 300 mg) omalizumab.

Treatment of patients with evidence of mast cell-mediated itch in the absence of hives with omalizumab.

PURPOSE: The presence of wheals or hives has been viewed as a hallmark symptom of urticaria, a highly debilitating disease. This study explores our experience with omalizumab in patients with apparent mast-cell mediated pruritus in the absence of hives. MATERIALS AND METHODS: This is a retrospective case series examining all patients with mast cell-mediated pruritus in the absence of hives from April 2022 to May 2024 at a tertiary referral clinic at Icahn School of Medicine at Mount Sinai in New York. Peak pruritus-numerical rating scale (PP-NRS) itch score changes over time were recorded and analyzed. RESULTS: Six patients (67% women; mean [SD] age, 47.67 [13.52] years) were included in the analysis. The median [IQR] pruritus PP-NRS itch score before omalizumab injection was 9 [6 - 10] and the final median [IQR] PP-NRS itch score was 2.5 [0 - 5]. The mean [SD] reduction in the PP-NRS itch score was 6 [3.16]. CONCLUSIONS: This study suggests that patients with evidence of mast cell-mediated pruritus can be identified based on clinical features and may benefit from omalizumab therapy.

Omalizumab for the reduction of allergic reactions to foods: a narrative review.

The frequency of food allergies varies between 2% and 10%, depending on characteristics including age, region, race, and method of diagnosis self-reported by patients or oral food challenges (OFCs). The most common allergies reported are tree nuts (1.2%), milk (1.9%), peanuts (2.2%), and shellfish (1.3%). Omalizumab injection has now been approved by the FDA for the treatment of immunoglobulin E-mediated food allergies in specific adults and children aged one year or older. This medication reduces the risk of allergic reactions (Type I), which can include anaphylaxis, when an individual accidentally encounters one or more food allergens. Omalizumab functions by binding to IgE and altering IgE-mediated pathways, which lessens IgE's capacity to cause allergic reactions. Promising outcomes from clinical trials and case studies include lowered anaphylactic risk and enhanced tolerance to allergens. Omalizumab, however, may have adverse effects; thus, close observation is required. Overall, this review sheds light on the efficacy, safety, and clinical implications of omalizumab, highlighting its potential as a useful intervention for IgE-mediated food allergies.

Unveiling Treatment Response Predictors in Predominant Subtypes of Chronic Inducible Urticaria.

INTRODUCTION: Chronic inducible urticaria (CIndU) is a subtype of chronic urticaria (CU), which requires specific triggers to occur. Despite their common occurrence, treatment response rates and predictors of treatment responses are largely lacking in the literature. This study evaluates antihistamine (AH) and omalizumab response rates in the most common CIndU subtypes and examines whether certain features can predict treatment responses. METHODS: We retrospectively analyzed CU patients with at least one CIndU subtype and performed comparisons between subgroups, in a total of 423 patients (70% CIndU, 30% chronic spontaneous urticaria [CSU] plus CIndU). RESULTS: The treatment response rates in CIndU were 51.6%, 51.5%, and 86.5% with standard-dose second-generation H1-antihistamines (sgAHs), updosed/combined sgAH, and omalizumab, respectively. Overall AH response was higher in CIndU than CSU plus CIndU (78.3% vs. 62%, p = 0.002) and in symptomatic dermographism (SD) and cold urticaria (ColdU) than cholinergic urticaria (ChoU) (83.2% vs. 78.3 vs. 60.9%, p = 0.04). AH-refractory patients had a longer disease duration (45.2 ± 56.7 months vs. 37 ± 51.9 months, p = 0.04), more angioedema, accompanying CSU, mixed CIndU subtypes (37.5% vs. 21.1%, p = 0.003; 45.1% vs. 27.1%, p = 0.002; 8.8% vs. 2.4%, p = 0.014), and lower baseline urticaria control test scores (5.86 ± 3.3 vs. 8.6 ± 3.6, p < 0.001) than AH-responsive patients. CONCLUSION: CIndU exhibits a good response to both AHs and omalizumab. Notably, the response to AHs is more pronounced in SD and ColdU compared to ChoU. Disease duration, angioedema, accompanying CSU, mixed CIndU, and lower baseline UCT scores may be used to predict AH treatment outcome in CIndU.

Efficacy and safety of subcutaneous immunotherapy combined with omalizumab in children with dust mite-induced asthma.

OBJECTIVE: To evaluate the benefits of combining omalizumab with specific immunotherapy (SCIT) in the treatment of children with bronchial asthma. METHODS: In this study, 83 children with asthma were treated at the Allergy Department of Qingdao University from January 2019 to February 2020. Participants were divided into three groups: SCIT, combination (omalizumab + SCIT), and control (standard asthma medications). We assessed Asthma Control Questionnaire (ACQ) scores, Visual Analogue Scale (VAS) scores, and lung function at baseline, 24 wk, and 48 wk. Additionally, asthma medication scores were compared at 24 and 48 wk. Adverse reactions were monitored in both the SCIT and combination groups. RESULTS: The combination group demonstrated lower ACQ scores at both 24 and 48 wk, and improved VAS scores at 48 wk compared to the other groups. Additionally, lung function parameters (FEV1 and FEF50) showed significant improvement in the combination group. Reduced asthma medication scores were noted in the combination group at 24 and 48 wk. Local adverse reactions were fewer in the combination group, and no systemic adverse reactions were reported. CONCLUSION: Combining omalizumab with SCIT provides quicker asthma control, lowers medication requirements, and enhances lung function with fewer adverse effects, making it a safe and effective treatment for children with bronchial asthma.

Relapsing Eosinophilia in a Severe Allergic Asthma Patient on Biological Therapy.

Background: Severe asthma often remains uncontrolled despite optimized inhaled treatment. The rise of biologic therapy in severe asthma represented a major advance for the disease management. However, correct phenotyping and monitoring of severe asthma patients is key to the success of targeted biologic therapy. Materials and Methods: We present the case of a 63-year-old female, never a smoker, diagnosed with asthma at the age of 45 and associated persistent mild rhinitis, without other notable comorbidities. She was prescribed medium-dose ICS/LABA, administered inconstantly in the first years after the diagnosis, with poor overall control of the disease. After several exacerbation episodes, treatment compliance improved, but the control of the disease remained poor despite adding an antileukotriene. In January 2019, she presented an exacerbation episode requiring treatment with oral corticosteroids (OCS) and she was afterwards put on high-dose ICS/LABA and continued the antileukotriene. She was referred for a skin allergy test, which revealed mild sensitization to Dermatophagoides pteronyssinus and farinae, with a total IgE level of 48.3 IU/mL. The blood eosinophil level was 270 cells/mm3. The lung function was variable, going from mild impairment to severe fixed obstruction during exacerbations. Despite optimized inhaled treatment, good adherence and inhaler technique, and allergen avoidance strategies, asthma control was not achieved, and she continued to experience severe episodes of exacerbation requiring OCS. Results: In October 2019, she was initiated on biologic therapy with omalizumab, which allowed asthma control to be achieved and maintained for 18 months, with preserved lung function, good symptom control, no exacerbations and slightly elevated blood eosinophil level (340-360 cells/mm3). In April 2021, she started experiencing exacerbation episodes requiring OCS (three episodes within 6 months), with a progressive increase in blood eosinophil level (up to 710 cells/mm3), and progressive deterioration of asthma control and lung function, despite continuation of previous therapy. A specific IgE test against Aspergillus was negative, and total IgE level was 122.4 IU/mL. In December 2021, the patient was switched from omalizumab to benralizumab. Asthma control was again achieved, lung function improved significantly and the patient did not experience any other exacerbation episodes up until today, which allowed for a reduction in ICS dose. Intriguingly, a relapsing eosinophilia was also noted under anti-IL5-R treatment prior to the dose administration, but with preserved asthma control. Conclusions: This case underscores the pivotal role of meticulous phenotyping in severe asthma management on one side, and careful monitoring of patient evolution and possible side effects of treatment on the other side. By showcasing how diverse inflammatory pathways can coexist within a single patient and impact treatment outcomes, it highlights the necessity of tailored biologic therapy for sustained control.

Comparison of the Efficacy of Omalizumab and Mepolizumab in Non-Steroidal Anti-Inflammatory Drug-Exacerbated Respiratory Disease.

INTRODUCTION: Non-steroidal anti-inflammatory drug-exacerbated respiratory disease (N-ERD) is heterogeneous in both phenotypes and endotypes. Due to insufficient head-to-head comparison studies, it is hard to decide which biological to initiate. This study aimed to compare the efficacy of omalizumab and mepolizumab which can be used in the treatment of patients with severe eosinophilic asthma diagnosed with N-ERD. METHODS: The population of this observational, cross-sectional study comprised of N-ERD patients who received omalizumab or mepolizumab for at least 6 months for severe asthma. Outcomes included the asthma control test (ACT), and sino-nasal outcome test scores (SNOT-22), blood eosinophil counts at initiation of biological treatment (T0, baseline) and at the end of 6th months (T6). Adverse effects related to biological treatment and changes of oral corticosteroids dose was recorded. RESULTS: The study included a total of 22 patients, of whom 11 received mepolizumab and 11 received omalizumab. The change in ACT, SNOT-22, eosinophil counts, and adverse effects related to biologicals were similar at T6 (p = 0.606, p = 0.168, p = 0.05, p = 0.053, respectively). However, when examining the SNOT-22 and ACT based on the cumulative distribution curve (SUCRA), mepolizumab (SUCRA value: 0.61, 0.72, respectively) demonstrated greater efficacy compared to omalizumab (SUCRA value: 0.19, 0.35, respectively). The oral corticosteroids discontinuation rate was similar between the two groups (p = 0.05). CONCLUSION: We found both omalizumab and mepolizumab to be effective in treatment; however, we determined that mepolizumab may have a potential superiority in efficacy.

Evaluation of multiple-flows exhaled nitric oxide and its clinical significance in severe asthmatic patients treated with biologics: a prospective real-life study.

BACKGROUND: Specific biomarkers, such as eosinophilia in peripheral blood or fractional exhaled nitric oxide (FeNO), can guide us in the choice of biologic therapy, allowing a more personalized approach. Although there are multiple evidences in the literature about the role of FeNO as a predictor of response to different biologic treatments, there are no data on the relationship between FeNO changes and clinical response to the four biologic drugs currently in use. OBJECTIVE: To evaluate and to compare the expression of multiple-flows FeNO parameters in a cohort of patients with severe asthma (SA) before and during the treatment with biologics to evaluate the performance of these biomarkers in predicting the achievement of clinical remission. METHODS: We prospectively enrolled 50 patients with severe asthma eligible for biologic therapy. Patients underwent clinical and functional monitoring at baseline (T0) and after 1, 6, and 12 months of treatment (T1, T6, T12), including multiple flows FeNO assessment. RESULTS: A statistically significant reduction of FeNO50 values and J'awNO was observed only in benralizumab and dupilumab subgroups. Among biomarkers, the reduction of FeNO 50 values at T1 was associated with a higher probability of achieving clinical remission at T12 (p = 0.003), which was also confirmed by ROC curve analysis (AUC 0.758, p = 0.002; sensitivity 60% and specificity 74% for a reduction of 16 ppb). CONCLUSION: These data confirm the potential of this biomarker in predicting clinical response to biologic treatment in patients with severe asthma in order to guide clinical decisions and evaluate a shift to other biologic therapy.

The Cost-effectiveness of Omalizumab for Treatment of Food Allergy.

BACKGROUND: Omalizumab is an anti-IgE therapy newly approved by the Food and Drug Administration for allergen agnostic treatment of single or multiple food allergies in patients aged 1 year or older. OBJECTIVE: Evaluate the cost-effectiveness of omalizumab as a food allergy treatment. METHODS: We evaluated health and economic outcomes in Markov cohorts of simulated food allergic infants randomized to receive omalizumab using a 15-year horizon. Monte Carlo simulation was used (n = 40,000 subjects) to evaluate cost-effectiveness from a societal perspective, incorporating both a family-level and individual-level analysis. We included family-level analysis to incorporate a broad perspective for health utility change, given treatment effects likely benefit all parties at home (eg, caregivers, siblings), not just the patient, representing the sum of changes in all such persons. Supplemental analyses explored lower omalizumab cost and home initiation. We performed deterministic and probabilistic sensitivity analyses. RESULTS: In the family-level cohort analysis, omalizumab exceeded cost-effectiveness thresholds ($185,183/quality-adjusted life-years [QALY]). In a comparison of the omalizumab strategy (OMA) with the non-omalizumab strategy, the cost of OMA exceeded the non-omalizumab strategy ($315,020 vs $136,609) with greater incremental effectiveness (12.668 vs 11.699 QALY). In the individual-level analysis, the cost-effectiveness of OMA was $573,698/QALY. In base-case assessments, OMA was cost-effective (willingness to pay, $100,000/QALY) at a health state utility (HSU) improvement of 0.265. The value-based cost of OMA ranged from $14,166 to $23,791 when it was considered at the individual and family-unit levels. Requiring OMA administration in the clinic was not cost-effective (incremental cost-effectiveness ratio, $260,239). CONCLUSIONS: In the base case and at current pricing, omalizumab is not cost-effective, but it could be at a lower retail price or when use creates large health utility shifts in the family and patient.

A Case in which Eosinophilic Meningoencephalitis Occurred during Oral Corticosteroid Tapering and after Switching from Anti-IL-5 to Anti-IgE Treatment.

A 49-year-old man with severe eosinophilic asthma, sinusitis, and esophagitis was admitted with a sudden severe headache. The patient was diagnosed with eosinophilic meningoencephalitis based on frontotemporal abnormalities on brain magnetic resonance imaging and high eosinophil counts in the cerebrospinal fluid. His allergic-disease control levels were poor, requiring regular oral corticosteroid (OCS) use. He was switched from anti-interleukin (IL)-5 to anti-IgE therapy because of worsening urticaria and asthma symptoms during OCS tapering. We suspect this was a case of complex eosinophilic meningoencephalitis caused by the combination of OCS tapering and anti-IL-5 therapy cessation that acquired anti-IgE antibody sensitization based on positive drug-induced lymphocyte stimulation test results.

Clinical features and potential markers of disease in idiopathic non-histaminergic angioedema, a real-life study.

Idiopathic non-histaminergic acquired angioedema (InH-AAE) is a rare disease, with unknown etiology and pathogenesis, characterized by recurrent clinical manifestations and resistance to antihistamines and corticosteroids. We aim to evaluate clinical features and potential markers of disease in an Italian cohort of patients with InH-AAE. We enrolled 26 patients diagnosed with InH-AAE. Information about clinical features, treatments, routine laboratory investigations, immunological and genetic tests were collected. We assessed plasma levels of complement components, angiogenic and lymphangiogenic mediators, proinflammatory cytokines and chemokines, and activity of phospholipases A2. Finally, patients underwent nailfold videocapillaroscopy (NVC); both quantitative and qualitative capillaroscopic parameters were analyzed. Plasma levels of VEGFs were similar in healthy controls and in InH-AAE patients. ANGPT1 was decreased in InH-AAE patients compared to controls while ANGPT2 was similar to controls. Interestingly, the ANGPT2/ANGPT1 ratio (an index of vascular permeability) was increased in InH-AAE patients compared to controls. sPLA2 activity, elevated in patients with C1-INH-HAE, showed differences also when measured in InH-AAE patients. TNF-α concentration was higher in InH-AAE patients than in healthy controls, conversely, the levels of CXCL8, and IL-6 were similar in both groups. At the NVC, the capillary loops mainly appeared short and tortuous in InH-AAE patients. InH-AAE represents a diagnostic challenge. Due to the potential life-threatening character of this condition, a prompt identification of the potentially bradykinin-mediated forms is crucial. A better comprehension of the mechanism involved in InH-AAE would also lead to the development of new therapeutic approaches to improve life quality of patients affected by this disabling disease.

Omalizumab in combination with subcutaneous immunotherapy for the treatment of multiple allergies associated with attention-deficit/hyperactivity disorder: a case report and a literature review.

We describe the case of a 10-year-old boy with asthma (AS), accompanied by allergic rhinitis (AR), food allergy (FA), and combined attention-deficit/hyperactivity disorder (ADHD), who was treated at Shanghai Renji Hospital on 11 July 2020. The efficiency of the previous treatment with salmeterol/ticlosone was poor. Treatment with montelukast sodium resulted in development of neurological symptoms. Treatment with omalizumab in combination with subcutaneous immunotherapy (SCIT) was then initiated in our department based on anti-asthmatic therapy. Symptoms of asthma were completely controlled, and FA and AR symptoms improved. The treatment regimen led to a significant improvement in ADHD symptoms and the overall quality of life of the patient. The literature search was done in the PubMed database using "attention deficit/hyperactivity disorder/ADHD" and "asthma" as keywords, and we identified 47 relevant articles. In conclusion, our results show that treating asthma with omalizumab in combination with salmeterol/ticlosone and SCIT is efficient in controlling symptoms of multiple allergies and may lead to the improvement in ADHD symptoms and the overall quality of life of pediatric patients with ADHD. While current studies suggest that allergic diseases are closely related to ADHD, there is still a lack of studies or case reports of complete treatment protocols to provide clinical clues for management of the disease.

Chronic Spontaneous Urticaria: An Update on the Evaluation and Management.

Chronic spontaneous urticaria (CSU) affects 0.5% to 1% of the general population and is often managed by allergy and immunology specialists. Guidelines have evolved over the past several decades with an emphasis on decreasing extensive screening laboratory testing as they are of low-yield and cost-ineffective. The utility of biomarkers remains under investigation but total immunoglobulin E may be helpful in determining specific endotypes and response to omalizumab. Antihistamines and omalizumab remain the primary therapeutic options for CSU, but an expanding body of evidence supports the use of immunosuppressants and anti-inflammatory medications in refractory cases.