Childhood acute urticaria in northern and southern Europe shows a similar epidemiological pattern and significant meteorological influences.

Acute urticaria (AU) is a common condition that often presents in childhood. Although there is a general perception of cyclic annual trends in AU, no one has tried to identify any seasonal variation on its prevalence and incidence, associate environmental influences and impute geographic, ethnic, or even genetic features that may contribute to its onset. We aimed to analyze the influence of climate and geographic parameters on annual fluctuation of AU cases referred to the Emergency Departments (EDs) of Norwich (UK) and Heraklion (Crete, Greece), compare all identifiable potential triggers and severity, and calculate the prevalence and incidence of AU. Record-based data of all children up to 14 yr of age referred to both EDs between June 2005 and May 2007 were examined retrospectively. Demographic characteristics and any potential identifiable triggers of AU were recorded and compared. Poisson's regression was utilized to examine any influence of meteorological parameters on AU incidence. Edwards' test for seasonality was applied to identify any significant seasonal trend of the AU incidence within each city. Seven hundred and twenty-nine AU cases were identified (324 in Norwich and 405 in Heraklion), among 56,624 total referrals (28,931 and 27,693 cases, respectively). Respiratory infections were found to be the most commonly associated potential triggers of AU and food allergens the least. AU cases and incidence rates in both cities were equally distributed during the study period. A non-significant seasonal trend in AU incidence (October, April-May) was observed in Norwich, in contrast to a significant seasonal pattern (December, February-May) of AU in Heraklion. Temperature was inversely associated with AU incidence, while the statistically significant effect of relative humidity varied. Acute childhood urticaria shows a similar epidemiological pattern in northern and southern Europe regardless of the expected differences in genetic, geographic, and environmental background. Temperature and humidity are correlated with AU incidence. Seasonality of several acute respiratory viral infections, the most prominent associated trigger of AU, coincides with the observed AU seasonality, suggesting a potential linkage. However, this needs to be elucidated from larger epidemiological studies.

Narrowband ultraviolet B phototherapy is beneficial in antihistamine-resistant symptomatic dermographism: a pilot study.

BACKGROUND: Symptomatic dermographism is the most common type of physical urticaria. It can be severe and poorly controlled with H1 antihistamines in some patients. Photochemotherapy (psoralen plus ultraviolet [UV] A) may help the itch of dermographism but the effect of narrowband (NB) UVB therapy has not been previously studied. OBJECTIVES: We sought to examine the clinical efficacy of NB UVB therapy for itch and whealing in symptomatic dermographism and to assess the duration of the effect during 3 months of follow-up. METHODS: Eight patients (6 female) were enrolled into an open uncontrolled prospective study. Intensity of itching and whealing was assessed with visual analog scales and the whealing response was evaluated by testing with a dermographometer at pressures of 20, 36, and 60 g/mm2 on the upper aspect of the back. NB UVB phototherapy was given for 6 weeks 3 times weekly starting at 50% of minimal erythema dose with 20% to 0% increments as tolerated. Fexofenadine (180 mg/d) was taken during the run-in period and subsequently throughout the study and follow-up as required. Patients were followed for 3 months with regular assessments every 6 weeks after completion of phototherapy. RESULTS: All patients showed an improvement in itching at the end of NB UVB treatment (mean [SD] reduction 52.3% [31.6%]). Subjective assessment of whealing revealed a significant improvement in all but two patients (mean [SD] reduction 71% [54%]). There was a small and statistically significant improvement in cumulative dermographometer-induced wheal widths at the end of phototherapy (P = .038). A time trend for the relapse of symptoms within 12 and 18 weeks after completing phototherapy was significant for both visual analog scale scores but not for dermographometer-induced whealing. LIMITATIONS: The apparent rarity of antihistamine-resistant symptomatic dermographism limited the study to a small number of participants. The severity of the condition did not permit a controlled and blinded study design. CONCLUSIONS: NB UVB phototherapy is an effective second-line treatment for patients with severe symptomatic dermographism responding poorly to fexofenadine. This therapy can lead to subjective relief of pruritus and whealing and objective reduction of whealing. NB UVB phototherapy may restore symptom control with antihistamines in some patients.

Drug-induced urticaria.

Urticaria is characterised by transient swellings of the skin, which fluctuate over hours. Deeper swellings of the subcutaneous and submucosal tissue are known as angio-oedema. Drug-induced urticaria has been reported with a wide range of drugs and vaccines. NSAIDs and antibiotics are the drugs most commonly associated with urticaria, although reliable data from prospectively controlled studies is scarce. Spontaneous reports of drug-induced urticaria to the Committee on Safety of Medicines, UK, over a 40-year period also implicate bupropion, selective serotonin re-uptake inhibitor antidepressants, angiotensin-converting enzyme inhibitors (ACEI), H2 and H1 antihistamines, and systemic antifungals. New evidence suggests that selective COX-2 inhibitors may be tolerated in patients with aspirin-sensitive urticaria. The safety of angiotensin II receptor antagonists in patients with angio-oedema induced by ACEI has not yet been established.

Autoimmune urticaria.

A growing body of evidence shows that at least 40% of patients with unexplained (idiopathic) chronic urticaria have clinically relevant functional autoantibodies to the high-affinity IgE receptor on basophils and mast cells. The term "autoimmune urticaria" is used for this subgroup of patients presenting with continuous ordinary urticaria. This article reviews the evidence for the autoimmune hypothesis and other nonantibody serum histamine-releasing factors in the etiopathogenesis of urticaria; defines autoimmune urticaria; looks at how autoimmune urticaria fits into existing classifications of urticaria; proposes diagnostic criteria that may be useful to the clinician; and reviews the management implications for patients with this subset of chronic disease.

Classification of anti-FcepsilonRI and anti-IgE autoantibodies in chronic idiopathic urticaria and correlation with disease severity.

BACKGROUND: Circulating autoantibodies against FcepsilonRI, IgE, or both occur in approximately one third of patients with chronic idiopathic urticaria (CIU), but not all autoantibodies initiate histamine release. OBJECTIVE: We sought to classify patients with CIU into subsets on the basis of serum bioactivity and immunoreactivity and to examine the relationship between newly defined subtype and disease severity. METHODS: Sera from patients with CIU (n = 78), dermog-raphism (n = 15), and cholinergic urticaria (n = 10) and sera from healthy subjects (n = 39) were analyzed by means of Western blot analysis for anti-FcepsilonRI autoantibodies and for histamine release from basophils and dermal mast cells. In vivo reactivity of autologous serum was tested by means of intradermal injection, and CIU severity was determined on the basis of clinical interview. RESULTS: We classified sera from patients with CIU into 5 subsets: immunoreactive histamine-releasing anti-FcepsilonRI autoantibodies (n = 20 [26%]); immunoreactive anti-FcepsilonRI autoantibodies without histamine-releasing activity (n = 12 [15%]); anti-IgE-like autoantibodies (n = 7 [9%]); serum containing a mast cell-specific histamine-releasing factor (n = 7 [9%]); and sera with no identifiable factor (n = 32 [41%]). Patients with serum histamine-releasing activity had more severe urticaria than patients without such activity. Positive skin test responses to autologous sera were associated with histamine-releasing anti-FcepsilonRI autoantibodies but not with non-histamine-releasing anti-FcepsilonRI autoantibodies. Neither healthy subjects nor patients with dermographism or cholinergic urticaria had his-tamine-releasing anti-FcepsilonRI autoantibodies. CONCLUSION: These data support the specificity of functional anti-FcepsilonRI autoantibodies to CIU. The identification of distinctive subsets of patients suggests that other pathogenic mechanisms occur in CIU in addition to direct ligation of FcepsilonRI by autoantibodies causing dermal mast cell degranulation. Elucidating these mechanisms might lead to new treatments for CIU.

Chronic urticaria.

UNLABELLED: Chronic urticaria has a spectrum of clinical presentations and causes. About 50% of patients with "idiopathic" disease have histamine-releasing autoantibodies in their blood. The term autoimmune urticaria is increasingly being accepted for this subgroup of patients, in whom immunosuppressive therapies may be appropriate if conventional approaches to management are unsuccessful. This article reviews the classification, causes, and management of chronic urticaria in light of recent advances in the understanding of its etiology. LEARNING OBJECTIVE: At the conclusion of this learning activity, participants should have up-to-date knowledge of the classification, assessment, and management of chronic urticaria and understand where the concept of autoimmune urticaria fits into existing frameworks.