Urticaria is a rash, that typically involves skin and mucosa, and is characterized by lesions known as hives or wheals. In some cases there is an involvement of deep dermis and subcutaneous tissue that causes a skin/mucosa manifestation called angioedema. Urticaria and angioedema are very often associated: urticaria-angioedema syndrome. The acute episodic form is the most prevalent in the pediatric population, and it is often a recurrent phenomenon (recurrent urticaria). Acute episodic urticaria it is usually triggered by viruses, allergic reactions to foods and drugs, contact with chemicals and irritants, or physical stimuli. In many instances it is not possible to identify a specific cause (idiopathic urticaria). Chronic urticaria is a condition that can be very disambling when severe. In children is caused by physical factors in 5-10% of cases. Other trigger factors are infections, foods, additives, aeroallergens and drugs. The causative factor for chronic urticaria is identified in about 20% of cases. About one-third of children with chronic urticaria have circulating functional autoantibodies against the high affinity IgE receptor or against IgE. (chronic urticaria with autoantibodies or "autoimmune" urticaria). It is not known why such antibodies are produced, or if the presence of these antibodies alter the course of the disease or influence the response to treatment. Urticaria and angioedema can be symptoms of systemic diseases (collagenopathies, endocrinopathies, tumors, hemolytic diseases, celiachia) or can be congenital (cold induced familiar urticaria, hereditary angioedema). The diagnosis is based on patient personal history and it is very important to spend time documenting this in detail. Different urticaria clinical features must guide the diagnostic work-up and there is no need to use the same blood tests for all cases of urticaria. The urticaria treatment includes identification of the triggering agent and its removal, reduction of aspecific factors that may contribute to the urticaria or can increase the itch, and use of anti-H1 antihistamines (and/or steroids for short periods if antihistamines are not effective). In some instances an anti-H2 antihistamine can be added to the anti-H1 antihistamines, even if the benefits of such practice are not clear. The antileucotriens can be beneficial in a small subgroup of patients with chronic urticaria. In case of chronic urticaria resistant to all the aforementioned treatments, cyclosporine and tacrolimus have been used with good success. When urticaria is associated to anaphylaxis, i.m epinephrine needs to be used, together with antihistamines and steroids (in addition to fluids and bronchodilatators if required).