Chronic Urticaria Due to Thyroid Antibodies

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 LSU (Shreveport) Department of Allergy and Immunology

A 45 year-old Caucasian male is here for evaluation of urticaria for 6 weeks. He was prescribed two courses of oral prednisone which led to resolution of his symptoms, but the urticaria lesions reappeared when he decreased the dose to 5 mg a day. He reports 4 episodes of angioedema symptoms affecting his upper lip during the last 6 weeks, often occurring during exacerbations of his urticaria. The urticarial lesions occur daily and are worse in the afternoon.

Past medical history

His past medical history is positive for hypertension, hyperlipidemia, erectile dysfunction, and allergic rhinitis.

Medications

His medications include Levitra (vardenafil), lisinopril, simvastatin, levothyroxine, amlodipine, hydrocodone prn, triamterene/hydrochlorothiazide and two courses of prednisone.

He was advised to stop lisinopril and simvastatin and he did discontinue those two weeks ago.

The review of systems is negative apart from the history of present illness as above. He reports no shortness of breath, wheezing, chest tightness, chest pain or abdominal symptoms.

Physical examination

The physical examination is remarkable for 4-5 small urticarial lesions on both flanks in the abdominal area.

What is the most likely diagnosis?

This is a patient with chronic urticaria and angioedema for six weeks. He has been on ACE inhibitor (lisinopril) and simvastatin. Both medications were stopped 2 weeks ago.

What laboratory workup would you suggest?

We suggested laboratory work up in attempt to clarify the etiology of his condition and this includes CMP, CBC with differential and smear review, ANA, sedimentation rate, rheumatoid factor, TSH, T4, C1Q, C4 and C2 levels, CH50 level, C1 esterase inhibitor (qualitative and quantitative), H. pylori IgG antibody, thyroid autoantibodies (antimicrosomal and antithyroglobulin antibodies).

What treatment would you suggest?

We prescribed loratadine 10 mg po bid and strongly recommended he should stay off any ACE inhibitors and follow with his primary care physician for blood pressure control.

What happened next?

Thyroid autoantibodies were reported positive with "extremely high" titer. TSH level was normal.

Anti-TPO - Greater than 1000.0
(reference range 0-3.9 IU/mL)

Thyroglobulin antibody 219
(reference range 0-14 IU/mL)

TSH 2.8
(reference range 0.34-5.6 IU/mL)

The patient was referred to see an endocrinologist specialist again.

What did we learn from this case?

A workup including C1Q, C4 and C2 levels, CH50 level, C1 esterase inhibitor (qualitative and quantitative) is indicated in chronic urticaria patients who have concurrent angioedema symptoms.

Thyroid function tests and thyroid antibodies are indicated in selected patients with chronic urticaria.


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

References

Anti-FceR1 Autoantibodies in Chronic Urticaria

Published: 02/23/2010
Updated: 09/24/2010

4 comments:

Anonymous said...

"C1Q, C4 and C2 levels, CH50 level, C1 esterase inhibitor (qualitative and quantitative) is indicated in chronic urticaria patients who have concurrent angioedema symptoms." Disagree with above statement. C1 esterase inhibitor deficiency usually not seen in chronic urticaria and angioedema. At least according to NEJM review article by Alan Kaplan, TSH and Thyroid Ab. usually are sufficient for w/up. If C1 esterase inhibitor deficiency, C4 would be decreased. It seemed initial screening of C4 should be sufficient.

Anonymous said...

Regarding the above comment - specifically:

Re: "C1 esterase inhibitor deficiency usually not seen in chronic urticaria and angioedema."

C1 esterase inhibitor deficiency is the most common cause of hereditary angioedema (HAE) which can present at any age. Those patients typically do not have urticaria but some may have.

Re: "If C1 esterase inhibitor deficiency, C4 would be decreased. It seemed initial screening of C4 should be sufficient."

You can do "piecemeal" workup doing test by test over weeks or months... The other option is to order the relevant tests upfront and reach the final diagnosis quicker. Different styles and different speed...

Anonymous said...

Thank you for your response. Indeed different styles and different speed.

Anonymous said...

Thank you for posting these teaching cases and encouraging a discussion. Sometimes comments are at least as interesting as the article... :)