Urticaria can be a chronic and debilitating affliction and is a relatively common disorder affecting between 10-20% of the population. Common causes include reactions to medication, food allergen, physical stimuli and venoms.Urticaria can be acute or chronic.

Chronic urticaria lasts for more than 6 weeks and is commonly difficult to treat. The use of immunosuppressive agents for this disorder when antihistamines fail can result in significant morbidity. Recent advances in the pathogenesis, etiology, diagnosis and management of chronic urticaria have led to new paradigms in treatment of this disorder. Cyclosporine is often the most effective but has some unique adverse effects that may prevent it from being used in some patients. The use of intravenous immunoglobulin (IVIG) has proven effective in a variety of reports and we will review the mechanisms likely involved in the successful control of urticarial symptoms by immunomodulating therapy using IVIG.

In this review, we will discuss mechanisms and pathogenesis of urticaria and the specific role of intravenous immunoglobulin (IVIG) in this disorder, especially in refractory or steroid-dependent cases.

Asthma phenotypes have been developed to address the complexities of the disease. However, owing to a lack of longitudinal studies, little is known about the onset as well as the stability of phenotypes. Distinguishing phenotypes with regard to the severity or duration of the disease is essential.

A phenotype covers the clinically relevant properties of the disease, but does not show the direct relationship to disease etiology and pathophysiology.

Different pathogenetic mechanisms might cause similar asthma symptoms and might be operant in a certain phenotype. These putative mechanisms are addressed by the term 'endotype'. Classification of asthma based on endotypes provides advantages for epidemiological, genetic, and drug-related studies.

A successful definition of endotypes should link key pathogenic mechanisms with the asthma phenotype. Thus, the identification of corresponding molecular biomarkers for individual pathogenic mechanism underlying phenotypes or subgroups within a phenotype is important. Whether newly defined asthma endotypes predict the individual course of asthma has to be validated in longitudinal studies.

The accurate endotyping reflects natural history of asthma and should help to predict treatment response. Thus, understanding asthma endotypes might be useful in clinical practice.

Asthma is a heterogeneous outcome and how the condition should be measured to best capture clinically relevant disease in epidemiologic studies remains unclear. We compared three methods of measuring asthma in the Danish National Birth Cohort (n>50.000).

When the children were 7 years old, the prevalence of asthma was estimated from a self-administered questionnaire using parental report of doctor diagnoses, ICD-10 diagnoses from a population-based hospitalization registry, and data on anti-asthmatic medication from a population-based prescription registry. We assessed the agreement between the methods using kappa statistics.

Highest prevalence of asthma was found using the prescription registry (32.2%) followed by the self-report (12.0%) and the hospitalization registry (6.6%). We found a substantial non-overlap between the methods (kappa = 0.21-0.38). When all three methods were combined the asthma prevalence was 3.6%. In conclusion, self-reported asthma, ICD-10 diagnoses from a hospitalization registry and data on anti-asthmatic medication use from a prescription registry lead to different prevalences of asthma in the same cohort of children.

The non-overlap between the methods may be due to different abilities of the methods to identify cases with different phenotypes, in which case they should be treated as separate outcomes in future aetiological studies.