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).