[Urticaria in children]

The cumulative incidence of urticaria in children is close to 10%. Two forms are described: the superficial form and the deep form, or angioedema. In young children aged under 3 years, urticaria is commonly annular and ecchymotic, and is mistaken for erythema multiforme or acute hemorrhagic edema. Serum sickness-like reaction is a particular form of urticaria characterized by angioedema of the extremities, fever and arthralgia, and it is chiefly drug-induced (cephalosporins). With children, questioning and clinical examination are essential and, in most cases, reveal an etiology. The main causes of acute or recurrent urticaria are viral infections and/or drugs (non-specific histamine release), whereas chronic urticaria is mostly due to physical causes. In developed countries, parasitic infections are rarely the cause. Arguments in favor of a food allergy are as follows: a setting of atopy, onset within one hour of taking the suspect food, absence of fever or infection, a duration of less than 24 hours, possible association with other signs of anaphylaxis, and further recurrence with each new intake of the suspect food. First-line treatment of urticaria without signs of severity consists solely of non-sedating antihistamine (associated with removal of the cause where the latter has been determined). Nearly one-third of cases of urticaria in children progress over a prolonged period of more than 6 weeks, thus constituting chronic urticaria (most often a form of mild recurrent urticaria during episodes of infection and/or medication). Chronic urticaria is very rarely due to an underlying inflammatory disease or a genetic disease such as cryopyrinopathy, and first-line etiological assessment is usually limited to the following tests: CBC, sedimentation speed and/or CRP, and transaminases.