SELECTED ARTICLES FROM THE RECENT LITERATURE 2004

11/30/04

Chronic urticaria - reviewed

Summary
Background - Chronic urticaria (CU) is a common, often distressing and sometimes disabling condition. A cause for CU can only occasionally be found (reactions to foods, drugs, only rarely infections). Therefore most cases of CU are considered chronic idiopathic urticaria (CIU).

Findings - Kozel and Sabroe of the Netherlands and the UK reviewed current aspects of the diagnosis and management of CIU. Auto-antibodies against the high affinity IgE receptor (Fc epsilon R1) or less commonly anti-IgE itself are present in the sera of about 1/3 of CIU cases. The stimulus for this auto-immune response is not known nor are its relationship to prognosis and the responses to usual therapy.The diagnosis of CIU is based mainly on the history and physical exam with no need for extensive laboratory testing in most cases. CIU resolves spontaneously in 30-55% of cases within 5 years but can persist in others for a much longer time.

The mainstay of current treatment of CIU are non-sedating H1 antihistamines (AH) with use of low dose of the more sedating agent doxepin sometimes quite helpful at bedtime. The value of the addition of H2 antagonists or leukotriene antagonists to AH therapy is controversial. Cyclosporine can be effective in up to 75% of severe cases of CIU. Improvement in some severe cases of CIU with IV Ig or plasmapharesis therapy has been reported in small patient series but evidence from sizable, controlled studies is not yet available. Oral corticosteroids may be needed to control severe exacerbations, using the lowest doses feasible. Some physical urticaria/angioedema cases (particularly delayed pressure urticaria) may respond poorly to AH and need periodic corticosteroid therapy. There is anecdotal experience suggesting responses in some CIU patients to sulfasalazine, methotrexate, stanazolol and cyclophosphamide.

Reference
DRUGS 2004;64:2515-36

Editor's Comments
These comments made by authors with extensive experience in CIU are worthy of consideration. As the authors point out, we still know little about the exact initiating factors in CIU. The auto-immunity seen in CIU patients appears to be restricted mainly to that directed against Fc epsilon R1/IgE in 30-40% of cases and against thyroid components (particularly thyroid peroxidase) in 20-25% of cases.

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