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Chronic spontaneous urticaria is a self-limited, mast cell–mediated skin disorder marked by recurrent episodes of hives, angioedema, or both lasting 6 weeks or longer. Clinicians classify the condition as chronic inducible urticaria when specific physical stimuli, such as pressure, temperature changes, or vibration, trigger symptoms. Lesions typically present as pruritic pink-to-red papules or plaques that resolve within 24 hours without residual discoloration. Nearly 40% of patients experience concurrent angioedema, most often involving the lips, eyelids, genitals, or extremities. Although not life-threatening, chronic urticaria can significantly affect quality of life by disrupting sleep, daily activities, and emotional well-being. Diagnosis is primarily clinical, supported by a limited laboratory evaluation, typically including a complete blood count, erythrocyte sedimentation rate, C-reactive protein, and, when indicated, thyroid studies, to exclude systemic disease. Management emphasizes patient education, avoidance of aggravating factors, and symptom control with second-generation H1-antihistamines, with escalation to omalizumab, dupilumab, or cyclosporine for cases that remain refractory. This activity for healthcare professionals is designed to enhance the learners' understanding of the pathophysiology, clinical presentation, and diagnostic evaluation of chronic urticaria. Participants gain a deeper appreciation for differentiating urticaria from mimicking conditions, applying guideline-based management strategies, and implementing stepwise therapy for optimal symptom control. Learners also enhance their interprofessional communication and care coordination skills, thereby improving patient adherence, safety, and quality of life. Ultimately, participation in this activity better equips participants to deliver patient-centered, evidence-based care that reduces disease burden and enhances long-term outcomes in individuals with chronic urticaria. Objectives: Identify the clinical characteristics and underlying pathophysiology of chronic spontaneous and chronic inducible urticaria. Screen patients with chronic urticaria for potential triggers, comorbidities, and contributing factors using evidence-based diagnostic tools and assessments.

This activity for healthcare professionals is designed to enhance the learners' understanding of the pathophysiology, clinical presentation, and diagnostic evaluation of chronic urticaria. Participants gain a deeper appreciation for differentiating urticaria from mimicking conditions, applying guideline-based management strategies, and implementing stepwise therapy for optimal symptom control. Learners also enhance their interprofessional communication and care coordination skills, thereby improving patient adherence, safety, and quality of life. Ultimately, participation in this activity better equips participants to deliver patient-centered, evidence-based care that reduces disease burden and enhances long-term outcomes in individuals with chronic urticaria. Objectives: Identify the clinical characteristics and underlying pathophysiology of chronic spontaneous and chronic inducible urticaria. Screen patients with chronic urticaria for potential triggers, comorbidities, and contributing factors using evidence-based diagnostic tools and assessments. Implement current guideline-directed management strategies for chronic urticaria, including appropriate use of second-generation H1-antihistamines and escalation therapies. Coordinate follow-up and long-term management plans with the healthcare team to monitor treatment outcomes and prevent unnecessary interventions in patients with chronic urticaria. Access free multiple choice questions on this topic.

Chronic urticaria is a mast cell–mediated condition characterized by recurrent episodes of hives, angioedema, or both. Acute spontaneous urticaria lasts fewer than 6 weeks, whereas chronic spontaneous urticaria persists for 6 weeks or longer. Chronic inducible urticaria (CIU), or “physical urticaria,” is a subset of CIU triggered by specific physical stimuli, such as pressure, vibration, or temperature changes.[1] Clinically, urticaria presents as pruritic pink-to-red papules and plaques, often with central pallor or raised welts that are the same color, lighter, or darker than the surrounding skin, in individuals with darker skin tones.[1] Lesions may be widespread but are common in pressure-prone areas, and scratching can lead to excoriations or dermographism. Nearly 40% of patients develop simultaneous angioedema, which typically involves the lips, periorbital region, genitals, or extremities and often persists for up to 72 hours. Evaluation requires a detailed history and physical examination, with attention to disease duration, systemic features, and inducible subtypes. Most cases of chronic urticaria lack an identifiable external cause, and routine extensive testing is unnecessary. Laboratory evaluation is generally limited and may include a complete blood count, erythrocyte sedimentation rate, C-reactive protein, and thyroid studies, with additional testing based on clinical suspicion.[2] Management focuses on avoidance of exacerbating factors, symptom control with escalating doses of second-generation H1-antihistamines, and progression to omalizumab, dupilumab, or cyclosporin for refractory cases.[1] Clinicians reserve systemic corticosteroids for the short-term control of acute flares. Chronic urticaria is incredibly stressful for patients, impacting quality of life, school and job performance, sleep, and contributing to psychiatric comorbidities. Standardized tools such as the Urticaria Activity Score and Urticaria Control Test help clinicians assess patients' disease severity and treatment response.[3]

The etiology of chronic spontaneous urticaria (CSU) is heterogeneous and incompletely understood, reflecting a complex interplay of immunologic, infectious, environmental, and idiopathic factors. Most evidence supports an autoimmune basis, with fewer cases linked to external allergens, infections such as hepatitis A or C, or systemic diseases.[4][5][6][7][8][9][10][11] Bacterial antigens can stimulate autoreactive B and T cells, leading to the production of autoantibodies such as anti-high-affinity immunoglobulin (Ig) E receptor (FcεRI) or anti-IgE, which trigger mast cell degranulation. Additionally, chronic gastric infection may increase circulating levels of inflammatory cytokines, such as interleukin-6 and tumor necrosis factor α, as well as histamine-releasing factors, thereby amplifying urticarial symptoms. Associations with Heliobacter pylori and hepatitis A or C remain inconsistent. Immune complex formation and autoimmune activation primarily link hepatitis infections to urticaria. In hepatitis C, mixed cryoglobulinemia may manifest with urticarial vasculitis or chronic urticarial lesions. Viral-induced liver inflammation can alter complement activity and histamine metabolism, potentially worsening urticaria. CSU commonly coexists with autoimmune disorders such as systemic lupus erythematosus, cryoglobulinemia, systemic juvenile idiopathic arthritis, celiac disease, Sjögren disease, type 1 diabetes, and autoimmune thyroid disease, reflecting shared immune dysregulation.[6][12] Clinicians should maintain a high index of suspicion for underlying autoimmune disease in patients with CSU who present with systemic features such as arthralgia, fatigue, or abnormal laboratory markers. Atopic conditions, including allergic rhinitis, asthma, and atopic dermatitis, are also more prevalent in affected patients. However, they do not drive disease pathogenesis.[13] This association likely reflects a shared predisposition toward immune dysregulation and mast cell hyperreactivity rather than a direct allergic mechanism. Psychological stress, hormonal variations, nonsteroidal anti-inflammatory drugs, aspirin, and systemic comorbidities can also modulate disease activity.

Atopic conditions, including allergic rhinitis, asthma, and atopic dermatitis, are also more prevalent in affected patients. However, they do not drive disease pathogenesis.[13] This association likely reflects a shared predisposition toward immune dysregulation and mast cell hyperreactivity rather than a direct allergic mechanism. Psychological stress, hormonal variations, nonsteroidal anti-inflammatory drugs, aspirin, and systemic comorbidities can also modulate disease activity. Dermatographism is a wheal-and-flare reaction that occurs after firm stroking, scratching, or pressure applied to the skin and is usually idiopathic. However, some evidence suggests that bacteria, fungi, viruses, scabies, penicillin, and famotidine can precipitate dermatographism.[14][15] Delayed-pressure urticaria and angioedema can occur after prolonged sitting on hard surfaces, carrying heavy bags, wearing tight clothing, or walking for extended periods. Additional physical stimuli indicated in the etiology of chronic inducible urticaria are water (aquagenic urticaria), cold (cold urticaria), heat (local heat urticaria), exercise (exercise-induced urticaria and anaphylaxis), posture changes (postural urticaria), vibration (vibratory angioedema and urticaria), and sunlight (solar urticaria).

Affecting 1% of the global population, CSU is a significant global health concern, with a rising incidence and prevalence.[16] A recent population-based analysis reveals an incidence of 0.088 per 1000 person-years and a prevalence of 0.24% across pediatric and adult groups in the United States.[17] The disease burden is consistently higher in women aged 30 to 50 than in men, reflecting the recognized female predominance in autoimmune disorders.[17] Approximately 57% of patients with CSU develop only wheals, 37% have both wheals and angioedema, and the remaining 6% experience only angioedema.[16] Experts estimate the incidence of chronic inducible urticaria (CIndU) to be 0.5% of the population, and, like CSU, it is more common in women than men. Nearly 20% to 30% percent of adults with CSU also experience CIndU.[18]

The central pathophysiology of CSU involves the persistent activation and degranulation of cutaneous mast cells and basophils, which release histamine, prostaglandins, leukotrienes, cytokines, and chemokines. These mediators cause vasodilation and increased vascular permeability, leading to dermal edema, inflammatory cell recruitment, and the formation of pruritic wheals and angioedema. Most cases are autoimmune and fall into 2 main endotypes: type I (autoallergic) and type IIb (autoimmune). In type I CSU, IgE autoantibodies against self-antigens such as thyroid peroxidase or interleukin 24 cross-link FcεRI on mast cells, triggering degranulation.[5] In type IIb, IgG autoantibodies target either FcεRI or IgE directly, also activating mast cells. These mechanisms can coexist and occur in over half of patients with CSU.[5] Rarely, type III or IV hypersensitivity reactions contribute, as seen in urticarial vasculitis or autoreactive CD4+ T-cell responses against FcεRIα.[19] Nonimmunologic triggers activate mast cells without antibody or T-cell involvement. Physical stimuli, such as pressure, vibration, temperature changes, sunlight, or water, can provoke CIndU subtypes, including dermatographism, cold, cholinergic, solar, and aquagenic urticaria. The Mas-related G protein–coupled receptor X2 (MRGPRX2), complement fragments, or neuropeptides may also activate mast cells.[20] MRGPRX2, expressed on skin mast cells, responds to ligands including substance P, vasoactive intestinal peptide, eosinophil granule proteins, host defense peptides, and certain drugs such as opioids, neuromuscular blockers, and quinolones.

Nonimmunologic triggers activate mast cells without antibody or T-cell involvement. Physical stimuli, such as pressure, vibration, temperature changes, sunlight, or water, can provoke CIndU subtypes, including dermatographism, cold, cholinergic, solar, and aquagenic urticaria. The Mas-related G protein–coupled receptor X2 (MRGPRX2), complement fragments, or neuropeptides may also activate mast cells.[20] MRGPRX2, expressed on skin mast cells, responds to ligands including substance P, vasoactive intestinal peptide, eosinophil granule proteins, host defense peptides, and certain drugs such as opioids, neuromuscular blockers, and quinolones. Patients with CSU and the 185A>G mutation in MRGPRX2 exhibit a gain-of-function phenotype characterized by increased disease activity.[21] Additionally, an arginine residue at position 56 of HLA-DQA1 (OMIM146880) increases the risk of CSU and is associated with higher levels of IgG autoantibodies.[22] Likewise, polymorphisms in inflammatory and immune-related genes, such as IL-33 (OMIM 608678), NLRP3 (OMIM 606416), and CCL2 (OMIM 158105), have also been associated with an increased susceptibility to CSU, with some variants linked to higher disease risk and autoantibody positivity, but not necessarily to disease severity.[23][24][25] Mutations in ADGRE2 (OMIM 606100) underlie hereditary vibratory angioedema.[26] Functional polymorphisms in the FcεRIα promoter (OMIM 147140) and LTC4S (OMIM 246530) genes contribute to aspirin-induced urticaria, which may trigger or worsen symptoms in patients with chronic urticaria.[26]

The histopathological features of urticaria include interstitial edema involving the upper and mid-dermis, mixed inflammatory perivascular infiltrates, dilated venules, and lymphatic vessels that permit leakage of serum into the surrounding tissue (see Image. Histopathology of Urticaria). Angioedema shares similar features, though located in the lower dermis and subcutaneous tissue. A biopsy of the involved skin for histological examination is not a routine component in the evaluation of chronic urticaria; however, a biopsy may be necessary when the rash is atypical. Leukocytoclasis and vasculitis are not typically associated with chronic urticaria and should prompt consideration of alternative diagnoses.[27]

Urticaria is characterized by pruritic pink-to-red papules and plaques, typically with central pallor. These can vary in size and shape as the plaques coalesce together. Urticaria is fleeting, and each wheal remains for fewer than 24 hours without any residual ecchymosis or pigmentation.[28] There may be a predilection for pressure-prone areas such as the waistline, axilla, and groin. Still, urticaria can generally affect any part of the skin (see Image. Urticaria, Upper Arm). Secondary changes from scratching may be evident on examination of the skin, including excoriations, erosions, and hemorrhagic crust. Symptomatic dermographism can often be elicited on applying pressure with a blunt object (see Image. Dermatographism). Concurrent angioedema presents as subcutaneous or submucosal swelling in nondependent areas, most often involving the lips, periorbital region, genitals, or extremities. Unlike urticaria, angioedema is typically associated with discomfort, numbness, tingling, or pain rather than pruritus, and it can resolve over 72 hours.[28][29] Additional symptoms may include headache, fatigue, joint pain or swelling, wheezing, flushing, gastrointestinal symptoms, musculoskeletal pain, and palpitations.

Clinicians establish the diagnosis of CSU when patients experience recurring episodes of urticaria or angioedema lasting for 6 weeks or longer, in the absence of systemic disease. A comprehensive history and physical examination remain the cornerstone of evaluation in chronic urticaria, focusing on disease duration, systemic features, and inducible subtypes. Key points include lesion characteristics, duration, and the presence or absence of angioedema. When clinicians suspect CSU, the history should focus on identifying possible triggers and excluding systemic disease. Clinicians should inquire about new medications, such as antibiotics, nonsteroidal anti-inflammatory drugs, or hormonal therapies; recent infections; travel history; changes in health; atopic conditions; and a sexual history. Additionally, clinicians should screen for features of systemic disease such as fever, weight loss, arthralgias, arthritis, temperature sensitivity, abdominal pain, or bone pain, since urticaria or urticarial vasculitis can occasionally be the initial presentation of conditions like systemic lupus erythematosus, rheumatoid arthritis, celiac disease, autoimmune thyroid disease, and Sjögren disease. Routine laboratory investigations include a complete blood count with differential and an erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP). Generally, these tests will be normal in patients with chronic urticaria. However, approximately 10% of patients may have eosinopenia associated with basopenia, type IIb autoimmunity, more severe disease, and poor response to treatment with both second-generation H1-antihistamines and omalizumab.[30] The presence of eosinophilia suggests parasitic infection or an atopic disorder. Slight elevations in ESR or CRP are common in patients with CSU; however, significant elevations warrant further evaluation for an underlying systemic illness, such as an autoimmune, infectious, malignant, or rheumatologic condition. Some potential additional tests, based on clinical suspicion, may include the following: Antinuclear antibodies Anti–Sjögren-syndrome-related antigen A and anti–Sjögren-syndrome-related antigen B antibodies Anti-citrullinated peptide antibodies Antithyroglobulin and antimicrosomal antibodies Thyroid-stimulating hormone Rheumatoid factor Anti-tissue transglutaminase antibody and total IgA levels Hepatitis serology

Routine laboratory investigations include a complete blood count with differential and an erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP). Generally, these tests will be normal in patients with chronic urticaria. However, approximately 10% of patients may have eosinopenia associated with basopenia, type IIb autoimmunity, more severe disease, and poor response to treatment with both second-generation H1-antihistamines and omalizumab.[30] The presence of eosinophilia suggests parasitic infection or an atopic disorder. Slight elevations in ESR or CRP are common in patients with CSU; however, significant elevations warrant further evaluation for an underlying systemic illness, such as an autoimmune, infectious, malignant, or rheumatologic condition. Some potential additional tests, based on clinical suspicion, may include the following: Antinuclear antibodies Anti–Sjögren-syndrome-related antigen A and anti–Sjögren-syndrome-related antigen B antibodies Anti-citrullinated peptide antibodies Antithyroglobulin and antimicrosomal antibodies Thyroid-stimulating hormone Rheumatoid factor Anti-tissue transglutaminase antibody and total IgA levels Hepatitis serology H pylori stool antigen testing or urea breath test Serum protein electrophoresis Total tryptase level Abdominal ultrasound or computed tomography to identify bowel wall thickening in angiotensin-converting enzyme inhibitor-mediated angioedema Stool studies for ova and parasites Thyroid autoimmunity is more frequent in patients with CSU, though thyroid function is usually normal. Guidelines do not support routine thyroid testing unless clinical signs or symptoms suggest thyroid dysfunction, as the diagnostic yield is low and rarely leads to changes in management or improvement in urticaria symptoms.[1][28][31][32] However, some experts recommend routine thyroid testing in adults. Autoimmune thyroid disease is rare in children with CSU.

Thyroid autoimmunity is more frequent in patients with CSU, though thyroid function is usually normal. Guidelines do not support routine thyroid testing unless clinical signs or symptoms suggest thyroid dysfunction, as the diagnostic yield is low and rarely leads to changes in management or improvement in urticaria symptoms.[1][28][31][32] However, some experts recommend routine thyroid testing in adults. Autoimmune thyroid disease is rare in children with CSU. Additionally, patients may initially feel that foods are the underlying cause of their urticaria. However, IgE-mediated food reactions are rarely the cause of CSU, and symptoms are most likely due to dietary variations, leading to fluctuations in symptoms. Testing for food allergy is not necessary; however, elimination diets or blinded challenge tests may be helpful in suspected pseudoallergen sensitivity. Broad autoantibody panels, routine biochemistry, and infection screening are unnecessary unless prompted by clinical suspicion. Likewise, a skin biopsy is unwarranted unless the lesions are painful, atypical, or accompanied by fever or arthralgia, which raises concern for urticarial vasculitis (see Image. Urticarial Vasculitis). In cases of angioedema without urticaria, C4 levels are warranted to evaluate for hereditary or acquired angioedema. Depressed levels should prompt measurement of C1 inhibitor antigen and C1 esterase inhibitor levels. Please see StatPearls' companion topic, "Angioedema," for an in-depth discussion on the evaluation of angioedema. For patients with CIndU, the following represent the recommended diagnostic challenge tests if history alone is not adequate to establish the diagnosis: Aquagenic urticaria: Applying a water compress at 35 °C to the skin of the upper body for 30 minutes may reveal 1 to 3 mm perifollicular wheals. Cholinergic urticaria: Methacholine intradermal challenge (low sensitivity) or partial immersion in hot water at 42 °C will reveal 1 to 3 mm wheals and occasionally large flares. Dermatographia: Stroking of skin with a firm object, such as a tongue blade, causes a wheal at the site within 1 to 3 minutes. Delayed pressure urticaria: Hanging a 7-kg weight over the shoulder for 10 or 15 minutes results in an area of angioedema within 2 to 12 hours. Vibratory urticaria: Placing a vortex mixer on the forearm for 4 minutes will cause angioedema.

Dermatographia: Stroking of skin with a firm object, such as a tongue blade, causes a wheal at the site within 1 to 3 minutes. Delayed pressure urticaria: Hanging a 7-kg weight over the shoulder for 10 or 15 minutes results in an area of angioedema within 2 to 12 hours. Vibratory urticaria: Placing a vortex mixer on the forearm for 4 minutes will cause angioedema. Cold urticaria: Placing ice cubes or an ice pack on the forearm for 5 minutes will cause urticaria at the site during rewarming. Solar urticaria: Phototesting with ultraviolet A or B light will cause urticaria at the challenge site. Exercise-induced urticaria: An exercise challenge, such as treadmill exercise, will reproduce symptoms.[32]

Pharmacologic Therapy The goal of pharmacologic therapy is to control symptoms by preventing mast cell degranulation and mitigating the effects of mediators released during CSU.[33] Current guidelines recommend that treatment in children mirror adult approaches, with attention to age-appropriate dosing and safety. First-Line therapy Guidelines recommend regular, scheduled use of second-generation H1-antihistamines (eg, cetirizine, loratadine, and fexofenadine) at standard doses for both CSU and CIndU.[34] Daily use of second-generation antihistamines is more effective than on-demand use for achieving and maintaining complete control of CIndU subtypes. Regular dosing consistently suppresses histamine-mediated symptoms and reduces the risk of unpredictable flares, even when triggers are known and exposures are intermittent. The American Academy of Allergy, Asthma, and Immunology (AAAAI) recommends daily dosing for most patients, as it provides more consistent symptom suppression and reduces the risk of breakthrough episodes. For patients with infrequent or predictable exposures, clinicians can consider on-demand antihistamines before anticipated triggers. Still, this strategy is less effective for disease control and does not reliably prevent breakthrough episodes as well as daily dosing. First-generation antihistamines are no longer first-line due to anticholinergic and central nervous system effects.[28] If symptoms persist, doses may be up-titrated every 2 to 4 weeks, up to 4 times the standard dose. Evidence for benefit is strongest for levocetirizine, desloratadine, and bilastine (not available in the United States). International guidelines: Recommend increasing a single antihistamine’s dose. AAAAI and the American College of Allergy, Asthma, and Immunology (ACAAI) guidelines: Allow combining 2 different second-generation antihistamines.[1][35][36][37] Pregnancy and pediatric use Cetirizine, levocetirizine, fexofenadine, and loratadine are considered safe in pregnancy, though data on up-dosing are limited.[38] These same agents, plus desloratadine, bilastine, and rupatadine, are approved for children, though more research is needed to confirm their safety at high doses.[39] Second-Line therapy

Pregnancy and pediatric use Cetirizine, levocetirizine, fexofenadine, and loratadine are considered safe in pregnancy, though data on up-dosing are limited.[38] These same agents, plus desloratadine, bilastine, and rupatadine, are approved for children, though more research is needed to confirm their safety at high doses.[39] Second-Line therapy If symptoms remain uncontrolled, clinicians should add omalizumab, an anti-IgE monoclonal antibody. Omalizumab is Food and Drug Administration-approved for adolescents and adults 12 and older. Off-label use in younger children shows favorable safety and similar efficacy.[28][40][41] The AAAAI/ACAAI guidelines suggest adding a second-generation H2 blocker such as famotidine or cimetidine, a leukotriene receptor antagonist like montelukast, or a first-generation H1 antihistamine at bedtime before starting omalizumab. Clinicians should avoid prescribing first-generation antihistamines in older adults due to falls and the risks associated with anticholinergic effects. Omalizumab is safe and preferred during pregnancy for refractory CSU.[42][43] Recommended doses are as follows: Cimetidine: 400 mg twice daily (20–40 mg/kg/day in children 5 and older; max 300 mg/dose) Famotidine: 20 mg twice daily (0.5 mg/kg/dose twice daily in children; max 40 mg twice daily) Montelukast: 10 mg nightly for adults; 5 mg for ages 6 to 14; 4 mg for ages 2 to 5; 4 mg granules for 6 to 23 months Doxepin: 10 to 25 mg at bedtime for adults and children 12 and older, titrated to 100 to 150 mg Hydroxyzine: 10 to 25 mg nightly; up to 100 to 200 mg daily (pediatric: 0.5 mg/kg; max 12.5 mg for children younger than 6 years and 25 mg for children 6 to 12 years Cyproheptadine: 2 mg for children younger than 6 years and 4 to 8 mg in children 6 and older If these options fail, discontinue ineffective therapies and initiate omalizumab at 300 mg subcutaneously every 4 weeks, continuing nonsedating antihistamines, tapering as tolerated. Patients should receive a prescription for an epinephrine autoinjector and education, given the risk of rare omalizumab-associated anaphylaxis. Dupilumab, approved for patients aged 12 and older, inhibits IL-4 and IL-13 in patients who do not respond to antihistamines.

If these options fail, discontinue ineffective therapies and initiate omalizumab at 300 mg subcutaneously every 4 weeks, continuing nonsedating antihistamines, tapering as tolerated. Patients should receive a prescription for an epinephrine autoinjector and education, given the risk of rare omalizumab-associated anaphylaxis. Dupilumab, approved for patients aged 12 and older, inhibits IL-4 and IL-13 in patients who do not respond to antihistamines. However, studies' results reveal that dupilumab is not effective in patients who did not tolerate or benefit from omalizumab, making dupilumab a potential choice if patients have concurrent conditions that may benefit from dupilumab, such as atopic dermatitis, urticarial dermatitis, chronic rhinosinusitis with nasal polyposis, or are concerned about the risk of anaphylaxis associated with omalizumab.[44] Remibrutinib, an oral Bruton tyrosine kinase inhibitor that works by blocking signaling through the high-affinity IgE receptor on mast cells and basophils, is now approved to treat CSU refractory to omalizumab. Third-Line therapy Clinicians can try cyclosporine for patients unresponsive to antihistamines and omalizumab. Though off-label, cyclosporin is effective, with a rapid onset and the potential for lasting remission. Clinicians should minimize dosing and duration to limit nephrotoxicity and hypertension.[45] Other less commonly used alternatives include mycophenolate, dapsone, sulfasalazine, phototherapy, methylxanthines, colchicine, methotrexate, and hydroxychloroquine.[46][47][48] Short courses of oral corticosteroids may be helpful for acute flares, whereas topical corticosteroids have no role in this setting.[49] Other considerations

Clinicians can try cyclosporine for patients unresponsive to antihistamines and omalizumab. Though off-label, cyclosporin is effective, with a rapid onset and the potential for lasting remission. Clinicians should minimize dosing and duration to limit nephrotoxicity and hypertension.[45] Other less commonly used alternatives include mycophenolate, dapsone, sulfasalazine, phototherapy, methylxanthines, colchicine, methotrexate, and hydroxychloroquine.[46][47][48] Short courses of oral corticosteroids may be helpful for acute flares, whereas topical corticosteroids have no role in this setting.[49] Other considerations Dihydropyridine calcium channel blockers, such as nifedipine, may help patients with CSU and hypertension by inhibiting T-cell proliferation and mast cell mediator release.[50] Healthcare professionals should regularly use validated tools such as the Urticaria Activity Score over 7 days (UAS7), the Urticaria Control Test (UCT), and the Chronic Urticaria Quality of Life Index (CU-QoL) to monitor disease control and quality of life.[28] Cold urticaria is considered more dangerous than other types of physical urticaria in patients being evaluated for CIndU because it carries a significant risk of systemic reactions, including anaphylaxis, particularly with generalized cold exposure such as swimming; the pooled prevalence of anaphylaxis in cold urticaria is approximately 21%. Other physical urticarias, such as symptomatic dermographism and delayed pressure urticaria, are generally limited to localized symptoms and rarely cause systemic reactions or anaphylaxis. Clinical guidelines from the AAAAI recommend that patients with cold urticaria receive counseling about the risk of severe reactions and be advised to consider carrying an epinephrine autoinjector, a precaution not routinely advised for most other physical urticarias. There is less evidence regarding the risk of life-threatening reactions in other forms of physical urticaria; however, cholinergic urticaria can also rarely cause severe systemic symptoms. Cold urticaria remains the most consistently associated with anaphylaxis among the physical urticarias.

The diagnosis of urticaria is typically straightforward, but atypical presentations warrant consideration of mimickers. Lesions lasting more than 24 hours, with infiltration, pigmentation, scaling, or associated with papules, vesicles, or hemorrhage, suggest something other than urticaria.[51] The following disorders present with urticaria-like lesions in addition to their other manifestations: Adult-onset Still disease: Evanescent, salmon-pink maculopapular rash with daily spiking fevers and systemic features Bullous pemphigoid (prebullous stage): Urticarial or eczematous phase preceding tense bullae Cryoglobulinemia: Cold-induced urticarial or vasculitic lesions with a potential association with connective tissue disease, hepatitis B and C infection, and lymphoproliferative disorders Cryopyrin-associated periodic syndromes: Characterized by urticarial rash, recurrent fevers, arthralgia, and systemic inflammation Gleich syndrome: Episodic angioedema with marked eosinophilia Hypereosinophilic syndrome: Persistent eosinophilia and multi-organ involvement, most commonly affecting the skin, lungs, heart, and nervous system, leading to symptoms such as rash, cough, dyspnea, cardiac dysfunction, or neuropathy Indolent systemic mastocytosis with skin involvement: Urticaria-like lesions plus systemic symptoms such as flushing, gastrointestinal upset, and osteoporosis Maculopapular cutaneous mastocytosis (urticaria pigmentosa): Persistent pigmented lesions with the Darier sign Polymorphic eruption of pregnancy: Presents in late pregnancy with intensely pruritic, erythematous papules and plaques that typically begin within abdominal striae and may spread to the thighs, buttocks, and arms, sparing the face, palms, and soles Schnitzler syndrome: Chronic urticarial rash with monoclonal gammopathy and systemic symptoms such as fever, arthralgia, and lymphadenopathy Systemic lupus erythematosus: Urticaria or urticarial vasculitis plus fever, weight loss, arthritis, lymphadenopathy, in addition to kidney, pulmonary, or cardiac manifestations Urticarial vasculitis: Painful weals persisting longer than 24 to 48 hours, often with purpura and systemic involvement Wells syndrome (eosinophilic cellulitis): Urticaria-like lesions evolving into edematous plaques with eosinophilia

Several biologics are under investigation for targeted therapy in chronic urticaria. Currently under investigation are the following: Benralizumab: Anti–IL-5 receptor α monoclonal antibody [52][53] Tildrakizumab: Anti–IL-23 monoclonal antibody [54] Barzolvolimab: Anti–KIT (anti–mast/stem cell growth factor receptor kit) monoclonal antibody [55] Ligelizumab: Anti–IgE antibody [56] Lirentelimab: Anti–Siglec-8 antibody Mepolizumab: Anti–IL-5 antibody At this time, barzolvolimab appears to be the most promising.[57]

CSU is typically self-limited, on average lasting 2 to 5 years.[58] The reported rate of remission in the first 12 months is approximately 30% to 50%.[59] However, up to 30% of patients continue to exhibit symptoms at 5 years.[60][61] Factors that portend a prolonged disease course include thyroid autoimmunity, concurrent angioedema, inability to achieve symptom control on standard doses of antihistamines, and possibly patients with hypertension, irrespective of the type of antihypertensive medication used, though the link with hypertension warrants additional investigation.[58][62][63][64]

Impaired quality of life, psychiatric comorbidities, and the burden of persistent symptoms are common in patients with CSU. Patients frequently report sleep disturbance, sexual dysfunction, limitations in daily activities, and reduced work or school performance. More than 40% have markedly impaired quality of life, and the overall burden is comparable to or worse than that of psoriasis or atopic dermatitis.[65][66] Psychiatric comorbidities are also common, with anxiety reported in up to 40% of patients, depression in 7% to 30%, and suicidal ideation in approximately 12% to 15%.[67] Treatment-related complications may arise from the long-term use of immunosuppressants such as cyclosporine, which can cause hypertension and nephrotoxicity, and corticosteroids, which may lead to hyperglycemia, cataracts, osteoporosis, adrenal insufficiency, immunosuppression, weight gain, avascular necrosis, and elevated blood pressure. Anaphylaxis occurs in approximately 1 to 2 per 1000 patients treated with omalizumab.[68] Other potential adverse effects of omalizumab include arthralgias, alopecia, eosinophilic granulomatosis with polyangiitis, and increased susceptibility to parasitic infections.[69] Some individuals experience a transient increase in pruritus after discontinuing cetirizine or levocetirizine, which typically resolves with medication reinitiation and gradual tapering. The economic and healthcare burden of CSU is substantial, with high direct and indirect costs resulting from frequent healthcare visits, chronic medication use, and lost productivity.

Patient education is essential for the effective management of chronic urticaria, including both CSU and CIndU. Patients should be reassured that the condition is benign, noncontagious, and rarely associated with severe systemic disease. Understanding that CSU is often self-limited—with remission occurring in up to half of patients within 1 year—can reduce anxiety and encourage treatment adherence. Education should emphasize treatment goals, including the fact that regular, scheduled use of nonsedating second-generation H1-antihistamines provides better symptom control than as-needed dosing. Patients should also understand that therapy aims to minimize symptoms and maintain quality of life while the condition follows its natural course. Avoidance and recognition of aggravating factors are crucial in reducing the frequency and intensity of symptoms. Common triggers include medications such as nonsteroidal anti-inflammatory drugs and aspirin, which may provoke nonallergic hypersensitivity reactions in a subset of patients. Intercurrent bacterial or viral infections can exacerbate urticaria; therefore, patients should understand the importance of early management of infections. Environmental factors, such as tight clothing, heat, and hot showers, can worsen pruritus and should be minimized. While not routinely recommended, some patients may choose a brief trial of a low-pseudoallergen diet to identify potential triggers. Foods and additives that may exacerbate symptoms include artificial colorings, flavor enhancers such as monosodium glutamate, preservatives like benzoates, sulfites, and tartrazine, as well as aged cheeses, cured or smoked meats, canned or fermented fish, certain fruits, tomatoes, salicylate-rich spices and herbs, chocolate, nuts, wine, beer, soft drinks, and vinegar-containing foods. For patients with CIndU, avoidance of triggering stimuli such as pressure, cold, heat, or sunlight is essential. Keeping a symptom diary helps identify patterns, triggers, and treatment response. Regular follow-up visits allow clinicians to assess disease control and treatment response using validated tools such as the UAS7, Urticaria Activity Score over 7 days, or the Urticaria Control Test, supporting shared decision-making and individualized care.

For patients with CIndU, avoidance of triggering stimuli such as pressure, cold, heat, or sunlight is essential. Keeping a symptom diary helps identify patterns, triggers, and treatment response. Regular follow-up visits allow clinicians to assess disease control and treatment response using validated tools such as the UAS7, Urticaria Activity Score over 7 days, or the Urticaria Control Test, supporting shared decision-making and individualized care. Clinicians should counsel patients not to self-increase antihistamine doses or combine therapies without medical guidance. Treatment escalation, such as high-dose antihistamines, omalizumab, or cyclosporine, should be performed in a stepwise manner under clinician supervision. Patients who are pregnant or breastfeeding should discuss medication safety with their healthcare provider, as several second-generation antihistamines, such as cetirizine, loratadine, and fexofenadine, are considered safe during pregnancy and lactation. Emotional stress, fatigue, and poor sleep are known to exacerbate urticaria; thus, stress management techniques, relaxation exercises, and adequate rest should be encouraged. Additionally, patients should also learn to seek immediate medical attention if they experience throat or facial swelling, difficulty breathing, dizziness, or widespread hives accompanied by hypotension, which may indicate anaphylaxis. Additionally, new systemic symptoms such as fever, joint pain, or swelling should prompt medical evaluation for possible autoimmune or vasculitic processes. With education, regular follow-up, and adherence to therapy, most patients can achieve effective long-term control of chronic urticaria and maintain a good quality of life.

Chronic urticaria, a mast cell–mediated disorder, causes recurrent episodes of pruritic wheals, angioedema, or both lasting 6 weeks or longer. The condition is classified as CSU when symptoms occur without an identifiable trigger, and as CIndU when symptoms result from specific physical stimuli, such as pressure, temperature extremes, or vibration. Lesions appear as pink-to-red papules or plaques with central pallor, which may coalesce and vary in color depending on skin tone. These lesions are often transient, lasting fewer than 24 hours, and commonly occur in areas prone to pressure. Nearly 40% of patients may experience angioedema, typically affecting the lips, periorbital region, genitals, or extremities, lasting up to 72 hours. Diagnosis relies primarily on clinical history and physical examination, with attention to duration, systemic features, and inducible triggers, as most cases lack an identifiable external cause. Routine laboratory evaluation is limited to a complete blood count, erythrocyte sedimentation rate or C-reactive protein, and possibly thyroid function tests, with additional testing guided by clinical suspicion. Management centers on trigger avoidance and symptom control, beginning with second-generation H1-antihistamines, which may be up-titrated for persistent symptoms. Patients with refractory symptoms receive omalizumab, dupilumab, or cyclosporin, while clinicians reserve short courses of systemic corticosteroids for acute flares. Standardized assessment tools, such as the Urticaria Activity Score and the Chronic Urticaria Quality of Life Questionnaire, aid in evaluating disease activity, monitoring response, and guiding therapy.

Routine laboratory evaluation is limited to a complete blood count, erythrocyte sedimentation rate or C-reactive protein, and possibly thyroid function tests, with additional testing guided by clinical suspicion. Management centers on trigger avoidance and symptom control, beginning with second-generation H1-antihistamines, which may be up-titrated for persistent symptoms. Patients with refractory symptoms receive omalizumab, dupilumab, or cyclosporin, while clinicians reserve short courses of systemic corticosteroids for acute flares. Standardized assessment tools, such as the Urticaria Activity Score and the Chronic Urticaria Quality of Life Questionnaire, aid in evaluating disease activity, monitoring response, and guiding therapy. Effective management of chronic urticaria relies on interprofessional collaboration and coordinated care among physicians, advanced practitioners, nurses, pharmacists, and allied health professionals. A patient-centered approach requires integrating clinical expertise, effective communication, and shared decision-making to optimize outcomes and ensure patient safety. Physicians and advanced practitioners play a crucial role in establishing a diagnosis, identifying triggers, and developing individualized treatment plans. They, along with other team members, also coordinate care among specialists, such as dermatologists, allergists, psychiatrists, and immunologists, to ensure comprehensive evaluation and continuity of care. Nurses contribute significantly by providing patient education and symptom monitoring, reinforcing adherence to medication regimens, and helping patients recognize potential triggers such as stress, infections, or medications. They serve as frontline communicators, identifying changes in the patient's condition and relaying information promptly to the care team to support timely interventions. Pharmacists ensure safe, evidence-based pharmacologic management by reviewing potential drug interactions, counseling patients on appropriate medication use, and supporting dose optimization of antihistamines and biologics. Their role extends to reinforcing adherence strategies and, when appropriate, identifying cost-effective treatment alternatives.

Nurses contribute significantly by providing patient education and symptom monitoring, reinforcing adherence to medication regimens, and helping patients recognize potential triggers such as stress, infections, or medications. They serve as frontline communicators, identifying changes in the patient's condition and relaying information promptly to the care team to support timely interventions. Pharmacists ensure safe, evidence-based pharmacologic management by reviewing potential drug interactions, counseling patients on appropriate medication use, and supporting dose optimization of antihistamines and biologics. Their role extends to reinforcing adherence strategies and, when appropriate, identifying cost-effective treatment alternatives. Interprofessional communication is essential for aligning treatment goals, avoiding duplicative testing, and reducing medication errors. Regular case discussions, shared electronic health records, and interdisciplinary meetings promote transparency and the development of unified management plans. Care coordination enhances patient-centered care by addressing both the physical and psychosocial impact of chronic urticaria. Collaborative efforts help patients understand their condition, manage expectations, and engage in self-care strategies, such as avoiding triggers and adhering to therapy. This coordinated, team-based approach enhances disease control, improves quality of life, and promotes patient safety, while fostering mutual respect among healthcare professionals, ultimately strengthening team performance and patient outcomes.