This update and revision of the international guideline for urticaria was developed following the methods recommended by Cochrane and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) working group. It is a joint initiative of the Dermatology Section of the European Academy of Allergology and Clinical Immunology (EAACI), the Global Allergy and Asthma European Network (GA²LEN) and its Urticaria and Angioedema Centers of Reference and Excellence (UCAREs and ACAREs), the European Dermatology Forum (EDF; EuroGuiDerm), and the Asia Pacific Association of Allergy, Asthma and Clinical Immunology with the participation of 64 delegates of 50 national and international societies and from 31 countries. The consensus conference was held on 3 December 2020. This guideline was acknowledged and accepted by the European Union of Medical Specialists (UEMS). Urticaria is a frequent, mast cell–driven disease that presents with wheals, angioedema, or both. The lifetime prevalence for acute urticaria is approximately 20%. Chronic spontaneous or inducible urticaria is disabling, impairs quality of life, and affects performance at work and school. This updated version of the international guideline for urticaria covers the definition and classification of urticaria and outlines expert‐guided and evidence‐based diagnostic and therapeutic approaches for the different subtypes of urticaria.

To cite this article: Maurer M, Weller K, Bindslev‐Jensen C, Giménez‐Arnau A, Bousquet PJ, Bousquet J, Canonica GW, Church MK, Godse KV, Grattan CEH, Greaves MW, Hide M, Kalogeromitros D, Kaplan AP, Saini SS, Zhu XJ, Zuberbier T. Unmet clinical needs in chronic spontaneous urticaria. A GA²LEN task force report. Allergy 2011; 66: 317–330. Abstract Chronic spontaneous urticaria, formerly also known as chronic idiopathic urticaria and chronic urticaria (CU), is more common than previously thought. At any time, 0.5–1% of the population suffers from the disease (point prevalence). Although all age groups can be affected, the peak incidence is seen between 20 and 40 years of age. The duration of the disease is generally 1–5 years but is likely to be longer in more severe cases, cases with concurrent angioedema, in combination with physical urticaria or with a positive autologous serum skin test (autoreactivity). Chronic spontaneous urticaria has major detrimental effects on quality of life, with sleep deprivation and psychiatric comorbidity being frequent. It also has a large impact on society in terms of direct and indirect health care costs as well as reduced performance at work and in private life. In the majority of patients, an underlying cause cannot be identified making a causal and/or curative treatment difficult. Nonsedating H₁‐antihistamines are the mainstay of symptomatic therapy, but treatment with licensed doses relieves symptoms effectively in <50% of patients. Although guideline‐recommended updosing up to fourfold increases symptom control in many patients, a substantial number of patients have only little benefit from H₁‐antihistamines. Consequently, there is a great need for new therapeutic strategies.

Hereditary angioedema (HAE) is a rare and disabling disease for which early diagnosis and effective therapy are critical. This revision and update of the global WAO/EAACI guideline on the diagnosis and management of HAE provides up‐to‐date guidance for the management of HAE. For this update and revision of the guideline, an international panel of experts reviewed the existing evidence, developed 28 recommendations, and established consensus by an online DELPHI process. The goal of these recommendations and guideline is to help physicians and their patients in making rational decisions in the management of HAE with deficient C1 inhibitor (type 1) and HAE with dysfunctional C1 inhibitor (type 2), by providing guidance on common and important clinical issues, such as: (1) How should HAE be diagnosed? (2) When should HAE patients receive prophylactic on top of on‐demand treatment and what treatments should be used? (3) What are the goals of treatment? (4) Should HAE management be different for special HAE patient groups such as children or pregnant/breast‐feeding women? and (5) How should HAE patients monitor their disease activity, impact, and control? It is also the intention of this guideline to help establish global standards for the management of HAE and to encourage and facilitate the use of recommended diagnostics and therapies for all patients.

Background and objectives: Urticaria is a frequent skin condition, but reliable prevalence estimates from population studies particularly of the chronic form are scarce. The objective of this study was to systematically evaluate and summarize the prevalence of chronic urticaria by evaluating population‐based studies worldwide.Methods: We performed a systematic search in PUBMED and EMBASE for population‐based studies of cross‐sectional or cohort design and studies based on health insurance/system databases. Risk of bias was assessed using a specific tool for prevalence studies. For meta‐analysis, we used a random effects model.Results: Eighteen studies were included in the systematic evaluation and 11 in the meta‐analysis including data from over 86 000 000 participants. Risk of bias was mainly moderate, whereas the statistical heterogeneity (I²) between the studies was high. Asian studies combined showed a higher point prevalence of chronic urticaria (1.4%, 95%‐CI 0.5‐2.9) than those from Europe (0.5%, 0.2‐1.0) and Northern American (0.1%, 0.1‐0.1). Women were slightly more affected than men, whereas in children < 15 years we did not find a sex‐specific difference in the prevalence. The four studies that examined time trends indicated an increasing prevalence of chronic urticaria over time.Conclusions: On a global level, the prevalence of chronic urticaria showed considerable regional differences. There is a need to obtain more sex‐specific population‐based and standardized international data particularly for children and adolescents, different chronic urticaria subtypes and potential risk and protective factors.

Background: Chronic spontaneous urticaria (CSU) can be debilitating, difficult to treat, and frustrating for patients and physicians. Real‐world evidence for the burden of CSU is limited. The objective of this study was to document disease duration, treatment history, and disease activity, as well as impact on health‐related quality of life (HRQoL) and work among patients with inadequately controlled CSU, and to describe its humanistic, societal, and economic burden.Methods: This international observational study assessed a cohort of 673 adult patients with CSU whose symptoms persisted for ≥12 months despite treatment. Demographics, disease characteristics, and healthcare resource use in the previous 12 months were collected from medical records. Patient‐reported data on urticaria and angioedema symptoms, HRQoL, and work productivity and activity impairment were collected from a survey and a diary.Results: Almost 50% of patients had moderate‐to‐severe disease activity as reported by Urticaria Activity Score. Mean (SD) Dermatology Life Quality Index and Chronic Urticaria Quality of Life Questionnaire scores were 9.1 (6.62) and 33.6 (20.99), respectively. Chronic spontaneous urticaria markedly interfered with sleep and daily activities. Angioedema in the previous 12 months was reported by 66% of enrolled patients and significantly affected HRQoL. More than 20% of patients reported ≥1 hour per week of missed work; productivity impairment was 27%. These effects increased with increasing disease activity. Significant healthcare resources and costs were incurred to treat CSU.Conclusions: Chronic spontaneous urticaria has considerable humanistic and economic impacts. Patients with greater disease activity and with angioedema experience greater HRQoL impairments.