Endocarditis Infecciosa

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Current reviews of allergy and clinical immunology
(Supported by a grant from GlaxoSmithKline, Inc, Research Triangle Park, NC)
Series editor: Harold S. Nelson, MD

Chronic urticaria: Pathogenesis and treatment
Allen P. Kaplan, MD Charleston, SC
This activity is available for CME credit. See page 32A for important information.

Patients previouslydesignated as having chronic idiopathic
urticaria are now divided into 2 groups: 40% to 50% with
chronic autoimmune urticaria, and the remainder with chronic
idiopathic urticaria. Patients in both groups may have
concomitant angioedema (approximately 40%). The
autoimmune subgroup has an association with antithyroid
antibodies and is caused by IgG antibody to the a subunit of the
IgE receptor (35%to 40%), usually reactive with unoccupied
IgE receptors, or IgG antibody to IgE (5% to 10%).
Complement activation augments histamine secretion by
release of C5a. The IgG subclasses that appear to be pathogenic
are IgG1, IgG3, and, to a lesser degree, IgG4, but not IgG2.
Histology of chronic urticaria (both subtypes) reveals
a perivascular non-necrotizing infiltrate of CD4+ lymphocytesconsisting of a mixture of TH1 and TH2 subtypes, plus
monocytes, neutrophils, eosinophils, and basophils. These cells
are recruited as a result of interactions with C5a, cell priming
cytokines, chemokines, and adhesion molecules. Suggested
therapy for patients with severe disease involves the use of highdose hydroxyzine or diphenhydramine when nonsedating
antihistamines are ineffective,supplemented by H-2
antagonists and leukotriene antagonists. The most severe
patient may require protracted treatment with low-dose
alternate-day steroid or cyclosporine. Cyclosporine can be
steroid-sparing when side effects are encountered or when use
of steroids is relatively contraindicated. Careful monitoring of
blood pressure, BUN, creatinine, and urinalysis is required. (J
Allergy ClinImmunol 2004;114:465-74.)
Key words: Chronic urticaria, skin, anaphylaxis, hives, autoimmune

The traditional definition of chronic urticaria is the
presence of hives for more than 6 weeks,1 and it is usually
assumed that hives are present most days of the week. The

From The Medical University of South Carolina, Department of Medicine,
Division of Pulmonary and Critical Care Medicine, Allergyand Clinical
Immunology.
Disclosure of potential conflict of interest: A. P. Kaplan—none disclosed.
Received for publication February 13, 2004; accepted for publication February
23, 2004.
Reprint requests: Allen P. Kaplan, MD, The Medical University of South
Carolina, Suite 812-CSB, Department of Medicine/Pulmonary, 96 Jonathan
Lucas St, Charleston, SC 92425. E-mail: kaplana@musc.edu.0091-6749/$30.00
Ó 2004 American Association of Allergy, Asthma and Immunology
doi:10.1016/j.jaci.2004.02.049

physically induced urticarias, such as dermatographism,
cold urticaria, and cholinergic urticaria, are commonly
included in this nonrestrictive definition, but this article
will only consider entities that are now considered to be
either chronic autoimmune urticaria or chronicidiopathic
urticaria. Patients with either of these latter forms of
chronic urticaria do not have IgE-mediated hypersensitivity to exogenous allergens as the cause of symptoms and
are distinct from the aforementioned physically induced
urticarias. Another distinction is pathogenic. Physically
induced hives, with the sole exception of delayed-pressure
urticaria, have no late-phase response afterthe initiating
urticarial response and therefore have hives lasting no
more than 2 hours, whereas individual lesions in patients
with chronic autoimmune urticaria or chronic idiopathic
urticaria last 4 to 36 hours. The exception, delayedpressure urticaria, is often seen accompanying either of the
2 types of chronic urticaria, but the diagnosis of chronic
urticaria requires the presence of...