Q:

5/29/2013
A 55 year-old woman ate Chobani peach yogurt for 1st time (usually eats Activa peach), with mixed nuts (brand new can, eats them three times a month), developed anaphylaxis 45 min later with edema. Skin testing and serum IgE neg to all nuts, milk, peaches. Has had no further episodes, and is eating her usual Activa peach brand and nuts without difficulty. Ingredient label states active cultures, peaches, cane juice, pectin, locust bean gum and natural flavor. Any thoughts as to the allergen? Thank you so much!

A:

Thank you for your inquiry.

The only two ingredients in the list you supplied that raised any suspicion are pectin and locust bean (guar) gum. For your interest, I have copied below references illustrating reports of anaphylaxis to these agents. None of the other ingredients raised suspicion.

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

Ann Allergy Asthma Immunol. 2006 Dec;97(6):759-60.
Pectin anaphylaxis and possible association with cashew allergy.
Ferdman RM, Ong PY, Church JA.
Source
Division of Clinical Immunology and Allergy, Childrens Hospital Los Angeles, Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, California 90027, USA.
Abstract
Background: Inhalation of pectin has been identified as a cause of occupational asthma. However, allergic reactions to orally ingested pectin have not been reported.
Objectives: To describe a child with pectin-induced food anaphylaxis and to discuss its possible relationship to cashew allergy.
Methods: A 3 1/2-year-old boy developed anaphylaxis once after eating cashews and later after eating a pectin-containing fruit "smoothie." He also has a history of generalized pruritus after eating grapefruit. Skin tests or radioallergosorbent tests (RASTs) were performed to pectin and other suspected food allergens.
Results: The child had a positive skin prick test reaction to pectin and a high RAST reaction to cashew and pistachio. He had a low-level positive RAST reaction to grapefruit. Results of allergy tests for the other potential food allergens were negative. The pectin in the smoothie was confirmed to be of citrus origin. Review of previous case reports of pectin-induced occupational asthma revealed several patients with allergies to and cross-reactivity with cashew.
Conclusions: Ingestion, not only inhalation, of pectin can cause hypersensitivity reactions. Cashew, and possibly pistachio, allergy may be associated with pectin allergy, and the possibility of pectin allergy should be considered in cashew- or pistachio-allergic patients who have unexplained allergic reactions.

Drugs.com
Adverse Reactions Pectin is a fermentable fiber that results in the production of short-chain fatty acids and methane. 59Occupational asthma associated with the inhalation of pectin dust is a well-recognized hazard. 60 , 61 , 62 , 63 Positive skin test results for pectin indicate that an immunoglobulin E (IgE)–mediated hypersensitivity reaction is probably involved. 63 Case reports exist of allergy (anaphylaxis) to pectin and cross-reactivity to cashews and pistachios. 55 , 64

J Investig Allergol Clin Immunol. 2011;21(1):77-8.
Urticaria and angioedema due to ingestion of carob gum: a case report.
Alarcón E, del Pozo MD, Bartolomé B, Navarro B, Escudero R, Gonzalez I, Blasco A, Lobera T.
Source
Allergy Section, Hospital San Pedro, Logroño, La Rioja, Spain.

Sincerely,
Phil Lieberman, M.D.

AAAAI - American Academy of Allergy Asthma & Immunology