Q:

8/24/2017
What proportion of patients with Oral Allergy Syndrome have symptoms with cooked stone fruits, compared to fresh fruits? What are the clinical implications, and how should they be evaluated? Are they likely to be sensitized to LTP? Will IgE testing to components, help in risk stratification?

A:

Thank you for your Ask the Expert question regarding “pollen fruit allergy syndrome” (PFS). Several reports in the literature were found that shed some light on this topic.

Webber and England published a review of PFS. They reported that 8.7% of patients with PFS may progress to have symptoms beyond the GI tract and 1.7% may go on to have anaphylactic shock. The authors also responded to a letter to the editor about the role of component-resolved diagnostics and the promise that they may hold as they become more available and better studied in terms of correlation with clinical outcomes.

In a report by Pravettoni et al, forty patients with oral symptoms to tomato were studied. Upon oral food challenge, 23 patient had mild oral allergy symptoms and 17 had severe oral symptoms. Of these 17 patients, 25% reported having allergic reactions to cooked tomatoes. Immunoblot testing of their sera found that they only reacted to LTP.

A report by Kleine-Tabbe et al studied 20 patients with birch-induced allergic rhinitis. These patients had allergic symptoms to soy as follows: PFS (14 patients), dyspnea (6), urticaria (6), facial swelling (17). Gly m 4 was found to be a major allergen. It is a pathogenesis-related (PR) protein which is related to birch pollen.

A study of 200 allergic rhinitis patients by Acero and colleagues noted that more than half of them had symptoms of PFS but no symptoms were induced by cooked or processed foods.

Component testing may be helpful. Santos and Brough discuss in vitro testing for food allergy in general, including component-resolve diagnostics, in a recent review in J Allergy Clin Immunol.

Webber CM and England RW. Ann Allergy Asthma Immunol 2010;104:101-8
Pravettoni V et al. J Agric Food Chem 2009 (22):10749-54
Kleine-Tabbe J et al. J Allergy Clin Immunol 2002;110:797-904
Acero R et al Clin Exp Allergy 2008; 38:1033-7

I hope this information is of help to you.

Jacqueline A. Pongracic, MD, FAAAAI

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