[Systemic urticaria in 2014]

Systemic urticaria are defined as urticaria, most often chronic, associated with systemic diseases. At present time, urticarial vasculitis and neutrophilic urticarial dermatosis associated to autoinflammatory syndromes are not considered to be subtypes of chronic spontaneous urticaria due to their distinctly clinical and histological characteristics as well different pathomechanisms. Sometimes, chronic urticaria is associated to thyroid autoimmunity. However, the majority of cases of chronic spontaneous urticaria have no discernible cause and further investigations are not necessary, as already suggested by some authors and French consensus conference more than 10 years ago.