Typical laboratory workup for chronic idiopathic urticaria and angioedema

Author: V. Dimov, M.D., Allergist/Immunologist and Assistant Professor at University of Chicago
Reviewer: S. Randhawa, M.D., Allergist/Immunologist and Assistant Professor at NSU

A 36-year-old male is at the clinic for evaluation of chronic urticaria and angioedema for the last 8 years. The initial workup 6-7 years ago was negative. He has hives every 2 days, and angioedema symptoms every month. He reports severe angioedema symptoms - mostly facial swelling - with "throat closing" 2-3 times per year, and then he needs to use his EpiPen. He reports no respiratory or abdominal symptoms and has no family history of angioedema. He takes NSAIDs for joint pain.

Past medical history

Chronic urticaria and angioedema, depression.


EpiPen PRN, loratidine 10 mg po daily (ran out of loratidine 10 days ago).

Physicial examination

Urticarial lesions on both arms and trunk.

Skin prick testing: negative.
Physical urticaria testing: no dermatographism

What is the most likely diagnosis?

Chronic urticaria and angioedema.

What would you recommend?

Cetirizine 10 mg po bid.
Ranitidine 150 mg po bid.

Instructed to use EpiPen in case of severe angioedema or respiratory symptoms. He does not want to take daily steroids. We asked him to stop NSAIDs and use acetaminophen (Tylenol) instead.

Laboratory tests

- Thyroid function tests (TFTs), for example, TSH, T4, and thyroid autoantibodies (antimicrosomal and antithyroglobulin antibodies)
- Total IgE
- Chronic urticaria index (positive if greater than 10) is a proprietary index, a positive result that makes autoimmune urticaria more likely
- C1q, C4, C2 levels
- C1-esterase inhibitor - qualitative and quantitative
- CH50, total hemolytic complement
- H. pylori workup, for example, H. pylori IgG (blood test). Diagnosis of Helicobacter pylori infection: 13C urea breath test or the stool antigen test as “test and treat strategy”. BMJ, 2012.
- RF

Diagnosis of Chronic Urticaria (click to enlarge the image).

Anti-FceR1 autoantibodies in chronic autoimmune urticaria: IgG against FceRI (receptor for IgE) (click to enlarge the image).

Why test for FceR1?

Approximately 45% of patients with chronic urticaria have an IgG autoantibody directed to the alpha-subunit of the high-affinity IgE receptor (chronic autoimmune urticaria, CAU) leading to cutaneous mast cell and basophil activation. Treatment of allergic asthma with omalizumab produces rapid reduction in free IgE levels and subsequent decrease in Fc epsilon RI expression on mast cells and basophils. In CAU, cross-linking of IgE receptors by autoantibody would be less likely, reducing cell activation and urticaria/angioedema.

In a study of 12 patients, Mean Urticaria Activity Score (UAS) declined significantly from baseline to the final 4 weeks of omalizumab treatment. Seven patients achieved complete symptom resolution. In 4 patients, mean UAS decreased, but urticaria persisted. One patient did not respond. Rescue medication use was reduced significantly, and quality of life improved (JACI, 2008).

Chronic spontaneous urticaria (CSU) is defined as the presence of urticaria with daily or almost daily symptoms for 6 weeks or more. CSU affects 0.1%-0.8% of the population. http://buff.ly/1rDwQ4P


Treatment of chronic autoimmune urticaria with omalizumab. Kaplan AP, Joseph K, Maykut RJ, Geba GP, Zeldin RK. J Allergy Clin Immunol. 2008 Sep;122(3):569-73.

Chronic urticaria: diagnosis and management. Khan DA. Allergy Asthma Proc. 2008 Sep-Oct;29(5):439-46.

Twitter comments

@Stolib: You check IgE levels or H. pylori studies in your chronic idiopathic urticaria (CIU) patients?

@Allergy: Depends on the clinical scenario: Typical laboratory workup for chronic idiopathic urticaria and angioedema http://goo.gl/rgDs

@Stolib: That is not how I was trained nor how I practice. I usually only lab pts only when they have failed antihistamines.

@Allergy: What if they have Hp infection that drives the process? By the time I see the CIU pts many of them have failed oral H1/H2 blockers.

@Stolib: Depends on what you considering failing antihistamines. I don't bother with HP unless symptoms suggest otherwise

@Allergy: Typical antihitsamine therapy in CIU: cetirizine 10 mg po bid and ranitidine 150 mg po bid. Would you like to describe your approach briefly, and I will publish it on AllergyCases.org, you retain authorship, of course.

@Stolib: My approach to CIU is outlined pretty well in this article written by my training program director: http://bit.ly/idYVip

@Allergy: Thank you for the reference - it's a free access article by David Khan. I will include it on AllergyCases.org http://goo.gl/JTlef

Published: 05/12/2010
Updated: 02/07/2012

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