10/30/2012
I'm following a 69 yo M with a working diagnosis of idiopathic angioedema.

Summary:
Recurrent AE of lips, unilateral tongue, and jaw line area since 1986. 1-2 times per yr at first. No complications (no airway compromise); sxs responded to additional antihistamine coverage and 20 mg of prednisone (1 dose). Increasing frequency over these past 6 mos; now as often as 2-3 times per month. One episode of bilateral tongue swelling with dysphagia requiring ER eval. No obvious triggers after an extensive history (including a food diary) was obtained. Has never had hives. No respiratory allergies.

- Zyrtec qod worked well for 10 yrs to control/prevent frequent episodes.
- Responded to prednisone 20 mg + Xyzal if acute swelling occurred.
- Recently seen in UCC for more severe sxs: Solumedrol, Benadryl to treat.

- Other meds: Allopurinol 300 mg qd
- PubMed search revealed 72 cases of recurrent AE in males >60 yo on daily Allopurinol; most of whom had been taking this meds x years; but, no references were given and no mention of this on FDA's page for Allopurinol
- pt is not taking ang OTCs, herbals, etc)

Skin test results 2006:
yolk = 2, celery = 2/3, spinach = 2/3, coffee = 2/3, mixed fish = 2/3, lamb = 2, peanut = 2, rice = 2, tuna = 2/3, walnut = 1, pistachio = 2

Note: Follow-up RAST tests to all above foods = class 0 except almond (class 1)

IgE 87 IU/ml
C1q; Total complement; C3; C4; C1 INH quant/functional=normal
ANA = 1.2 (1.0)
CBC: normal
CMP: normal

Latex RAST: class 0
Flaxseed RAST = 0/1

T3 uptake, T4, Free thyroxine index, TSH = normal
H. pylori antibodies = slight elevation (1.3) - > 1.0 = + test result
IgE = 86.9 (normal)
Thyroglobulin antibody = normal
Thyroid peroxidase antibody = slight elevation 38 (<35)

- Failed daily H1/H2 blockers in the past when symptoms were occurring more frequently.
- Scheduled for repeat food skin testing next week.

- Would you recommend any other lab studies?
- Do you have any recs for treatment?

Thank you very much for your help with this matter.

Thank you for your inquiry.

First of all, I think you have done due diligence in your search for a cause, and I do not feel any further laboratory evaluation is indicated. Based on the history and lab data obtained so far, this patient appears to have idiopathic angioedema. Unfortunately, as you well know, this accounts for the vast majority of cases of angioedema, and in such instances, the cause simply alludes us. In addition, also unfortunately, therapy for idiopathic angioedema leaves much to be desired since patients usually do not respond to antihistamine treatment. In fact, oftentimes they are resistant to all preventive therapy and quite often respond only to epinephrine injection for acute episodes.

More recently this form of angioedema has been called nonhistaminergic angioedema, and has been hypothesized to be due to activation of the contact system and therefore mediated by kinins. In fact, treatment with a bradykinin-2 receptor antagonist, icatibant, a drug we normally use for hereditary angioedema, has been found to be successful in this disorder (1).

Thus, one way to approach this patient if the symptoms are severe is to try icatibant if you can get it authorized for administration.

Except for this, there is no other approach that has been consistently successful in the management of cases such as the one you described.

Thank you again for your inquiry and we hope this response is helpful to you.

Reference:
1. Annals of Allergy, Asthma, and Immunology 2012; 108(6):460-461.

Sincerely,
Phil Lieberman, M.D.