Chronic urticaria is a common condition that can be very disabling when severe. A cause for
chronic idiopathic urticaria (CIU) is only infrequently identified. Potential causes include reactions to food and drugs,
infections (rarely) and, apart from an increased incidence of
thyroid disease, uncomplicated
urticaria is not usually associated with underlying systemic disease or
malignancy. About one-third of patients with CIU have circulating functional
autoantibodies against the high affinity
IgE receptor or against
IgE, although it is not known why such
antibodies are produced, or how the presence of such
antibodies alters the course of the disease or response to treatment. There are only a few publications relating to childhood
urticaria, but it is probably similar to the adult form, except that adult
urticaria is more common. The diagnosis is based on patient history and it is vital to spend time documenting this in detail. Extensive laboratory tests are not required in the vast majority of patients.
Chronic urticaria resolves spontaneously in 30-55% of patients within 5 years, but it can persist for many years. Treatment is aimed firstly at avoiding underlying causative or exacerbating factors.
Histamine H1 receptor antagonists remain the mainstay of oral treatment for all forms of
urticaria. The newer low-
sedating antihistamines desloratadine,
fexofenadine,
levocetirizine and
mizolastine should be tried first.
Sedating antihistamines have more adverse effects but are useful if symptoms are causing sleep disturbance. Low-dose dopexin is effective and especially suitable for patients with associated depression. There is controversy as to whether the addition of an
histamine H2 receptor antagonist or a
leukotriene antagonist is helpful. For CIU, second-line agents include
ciclosporin (
cyclosporine) [which is effective in approximately 75% of patients], short courses of oral
corticosteroids,
intravenous immunoglobulins and
plasmapheresis, although the last two were found to be beneficial in small trials only. Treatments for CIU with only limited or anecdotal supportive evidence include
sulphasalazine,
methotrexate, stanazol,
rofecoxib and
cyclophosphamide. The efficacy of photo(chemo)
therapy is controversial. Physical
urticarias may respond to
H1 receptor antagonists, although in delayed pressure
urticaria, and cold, solar and
aquagenic urticaria, the response may be disappointing. Second-line agents for physical
urticarias vary depending on the
urticaria and most have limited supportive evidence. The potential for spontaneous resolution, the variation in the disease activity and the unpredictable nature of the disease makes the efficacy of treatments difficult to assess.