12/10/2012
16-year-old girl has had recurrent anaphylaxis requiring hospital admission this year. She has known allergies to fish, egg and environmental allergies. Outgrew egg allergy age 7. Paternal aunt has recurrent anaphylaxis of unknown etiology. Allergic reactions are getting frequent and more severe.

Her first reaction was at age 2 to fish with hives. The next reaction was at age 7 with swelling of lips and tongue. She has had reactions at age 2, 7 and 14 requiring one Epipen autoinjector Rx and observation for a few hrs. These were related to fish in some form. This year she had four anaphylactic reactions. Two were related to fish but other two reactions- no trigger found. She gives herself Epipen at the earliest sign. Each reaction is getting more severe - starts with hives, swelling of lip and tongue and breathing difficulty. At emergency, she required treatment with 3-4 doses of epinephrine, IV steroids and Benadryl. Her BP drops significantly requiring admissions in ICU to stabilize her.

Summary of investigations done:
IGE is 327 KIU/L
RAST - dust mites 47.5 KIU/L
cat 18.9 KIU?L
mixed grass REACTIVE
C1ESTERASE INH and C4 is normal.
SERUM TRYPTASE level during and in between episodes is normal.
SPIROMETRY is normal.
Skin testing for foods confirmed fish allergy.
She is taking Ceterizine 20mg daily his year. She carries 3-4 Epipen with her.

My questions are:
Is there any other investigations to be done?
What else can be given to her prophylactically to prevent reactions?
Thank you for your help.

Thank you for your inquiry.

We have received several inquiries very similar to yours regarding patients who have had repeated, severe episodes of anaphylaxis of unknown cause. On August 31, 2012, there is an entry entitled “Evaluation of a patient with recurrent episodes of anaphylaxis of unknown cause.” The answer to this question would apply in great part to your patient. You can pull up this answer by going to the Ask the Expert website and typing “idiopathic anaphylaxis” into the search box. I would copy it for you here for your convenience, but it is rather lengthy.

As you can see from that previous answer, there is an excellent review of idiopathic anaphylaxis that appeared in a recent issue of Allergy and Asthma Proceedings which would be helpful to you. You can also see from that response that you have done an excellent workup, and only a few potential tests might be considered. These would be:

1. Skin testing to fresh foods by the prick-to-prick method in regards to those foods that she ate prior to the episodes of unknown cause.
2. Ordering a galactose-alpha-1,3-galactose (alpha-gal).
3. In spite of the fact that her serum tryptase levels have been normal, consideration should be given to a bone marrow if episodes continue, since systemic mastocytosis can occur in rare patients who do not demonstrate an elevated serum tryptase.

There are a number of drugs which have been employed as alternative therapies for recalcitrant cases who do not respond to antihistamine therapy. The standard therapy is a combination of H1 and H2 antagonists. To that, a mast cell stabilizing/antihistamine drug, ketotifen, can be added. This drug can be obtained from Canada, and the dose which I usually employ is 1 mg b.i.d. I usually add it to the standard antihistamine regimen.

Then, there are other drugs which have been employed including the daily administration of prednisone (for details see the reference cited above), methotrexate, mycophenolate mofetil, tacrolimus, omalizumab, and antileukotrienes.

Again, more details and further references are noted in the Ask the Expert response of August 2012.

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

Sincerely,
Phil Lieberman, M.D.