Cold urticaria (ColdU) is a common form of chronic inducible urticaria characterized by the development of wheals, angioedema or both in response to cold exposure. Recent research and guideline updates have advanced our understanding and management of ColdU. Today, its pathophysiology is thought to involve the cold‐induced formation of autoallergens and IgE to these autoallergens, which provoke a release of proinflammatory mediators from skin mast cells. The classification of ColdU includes typical and atypical subtypes. We know that cold‐induced wheals usually develop on rewarming and resolve within an hour and that anaphylaxis can occur. The diagnosis relies on the patient's history and cold stimulation testing. Additional diagnostic work‐up, including a search for underlying infections, should only be done if indicated by the patient's history. The management of ColdU includes cold avoidance, the regular use of nonsedating antihistamines and the off‐label use of omalizumab. However, many questions regarding ColdU remain unanswered. Here, we review what is known about ColdU, and we present important unanswered questions on the epidemiology, underlying pathomechanisms, clinical heterogeneity and treatment outcomes. Our aim is to guide future efforts that will close these knowledge gaps and advance the management of ColdU.

Background: Cold urticaria (ColdU), that is, the occurrence of wheals or angioedema in response to cold exposure, is classified into typical and atypical forms. The diagnosis of typical ColdU relies on whealing in response to local cold stimulation testing (CST). It can also manifest with cold‐induced anaphylaxis (ColdA). We aimed to determine risk factors for ColdA in typical ColdU.Methods: An international, cross‐sectional study COLD‐CE was carried out at 32 urticaria centers of reference and excellence (UCAREs). Detailed history was taken and CST with an ice cube and/or TempTest^® performed. ColdA was defined as an acute cold‐induced involvement of the skin and/or visible mucosal tissue and at least one of: cardiovascular manifestations, difficulty breathing, or gastrointestinal symptoms.Results: Of 551 ColdU patients, 75% (n = 412) had a positive CST and ColdA occurred in 37% (n = 151) of the latter. Cold‐induced generalized wheals, angioedema, acral swelling, oropharyngeal/laryngeal symptoms, and itch of earlobes were identified as signs/symptoms of severe disease. ColdA was most commonly provoked by complete cold water immersion and ColdA caused by cold air was more common in countries with a warmer climate. Ten percent (n = 40) of typical ColdU patients had a concomitant chronic spontaneous urticaria (CSU). They had a lower frequency of ColdA than those without CSU (4% vs. 39%, p = .003). We identified the following risk factors for cardiovascular manifestations: previous systemic reaction to a Hymenoptera sting, angioedema, oropharyngeal/laryngeal symptoms, and itchy earlobes.Conclusion: ColdA is common in typical ColdU. High‐risk patients require education about their condition and how to use an adrenaline autoinjector.

Special conditions associated with laboratory autoimmune testing are not well compatible with recent developments in regulatory frameworks such as EN/ISO 15189 accreditation or in vitro diagnostic medical device regulation (IVD-R). In addition, international recommendations, guidelines and disease criteria are poorly defined with respect to requirements on autoantibody testing. Laboratory specialists from Austria, Belgium, Croatia, Estonia, Finland, France, Germany, Greece, Hungary, Italy, Norway, Poland, Portugal, South Africa, Spain, Sweden, Switzerland, and The Netherlands collected information, reported national experience, and identified quality issues in relation to autoantibody testing that require consensus on interpretation of the regulatory frameworks and guidelines. This process has been organized by the European Autoimmunity Standardisation Initiative (EASI). By identifying the critical items and looking for a consensus, our objective was to define a framework for, in particular, EN/ISO accreditation purposes. Here, we present a review of current publications and guidelines in this field to unify national guidelines and deliver in this way a European handout on quality control and accreditation for laboratories involved in autoantibody testing. We focus on quality items that can be checked during accreditation visits. Despite various local varieties, we encountered an overwhelming dedication to quality assurance in all contributing countries.

Eyelid dermatitis (ED) affects a cosmetically significant area and leads to patients’ distress. Despite ongoing and recent research efforts, ED remains a multidisciplinary problem that needs further characterization. We aimed to evaluate the atopic eyelid dermatitis (AED) frequency in ED patients and to perform their clinical profiling. PubMed databases were searched from 01.01.1980 till 01.02.2024 to PRISMA guidelines using a search strategy: (eyelid OR periorbital OR periocular) AND (dermatitis or eczema). Studies with patch-tested ED patients were included. Proportional meta-analysis was performed using JBI SUMARI software. We included 65 studies across Europe, North America, Asia and Australia, with a total of 21,793 patch-tested ED patients. AED was reported in 27.5% (95% CI 0.177, 0.384) of patch-tested ED patients. Isolated ED was noted in 51.6% (95% CI 0.408, 0.623) of 8453 ED patients with reported lesion distribution, including 430 patients with isolated AED. Our meta-analysis demonstrated that the AED frequency in patch-tested ED patients exceeded the previous estimate of 10%. Isolated AED was noted in adult patients, attending contact allergy clinics. Future studies are needed to elucidate the global prevalence and natural history of isolated AED in adults.