Allergy information for: Pecan (Carya illinoinensis )

  • Name: Pecan
  • Scientific Name: Carya illinoinensis
  • Occurrence: Chopped nuts in foods and as garnishes. More information..
  • Allergy Information:

    Allergies to tree nuts and seeds tend to be of a more severe nature, causing life-threatening and sometimes fatal reactions. People with tree nut allergies also often suffer from reactions triggered by a number of different types of nuts, even though they do not come from closely related plant species. In general these allergies are triggered by the major proteins found in nuts and seeds which are resist processes such as cooking.

    There is also a milder form of tree nut allergy which is associated with birch pollen allergy, where symptoms are confined largely to the mouth, causing a condition called “oral allergy syndrome” (OAS). This condition is triggered by molecules found in tree nuts which are very similar to pollen allergens like the major birch pollen allergen called Bet v 1. These molecules tend to be destroyed by cooking, which can reduce the allergenicity of nuts and seeds for these allergic consumers.

    Reactions to nuts and seeds can also occur as a consequence of hidden nut ingredients or traces of nuts and certain seeds introduced as a consequence of food handling or manufacturing. As a result tree nuts and seeds have been included in Annex IIIa of the EU food labelling directive. The following (including products thereof) must be declared on a label if they have been deliberately included in a food:

    Almond, hazelnut, Walnut, Cashew, Pecan nut, Brazil nut, Pistachio nut, Macadamia nut Queensland nut, Mustard and Sesame seeds

    Temporary exceptions to the labelling rule (derogations) have been granted for

    Alcoholic berverages

  • Other Information: Nuts i.e. Almond, Hazelnut, Walnut, Cashew, Pecan nut, Brazil nut, Pistachio nut, Macadamia nut and Queensland nut and products thereof are listed in annex IIIa of the EU directive on labelling of foods.
  • Taxonomic Information: NEWT
  • Last modified: 18 October 2006

Reviews (0)

    References (0)

      Clinical History

      • Number of Studies:1-5
      • Number of Patients:1-5
      • Symptoms:

        Malanin et al. (1995) [105] reported one 8-year old girl who suffered from vomiting, hives, generalised urticaria and wheezing 15-20 minutes after ingestion of a pecan containing cookie

        Yunginger (1988) [568] reported fatal anaphylaxis of a 16-year old male

        Gillespie et al (1976) [342] reported urticaria, angioedema, asthma in a study of 18 patients allergic to tree nuts.

        Note that more than 20 patients are reported as allergic to pecan (see below) but their symptoms are not described separately from those due to other tree nuts.

      Skin Prick Test

      • Number of Studies:1-5
      • Food/Type of allergen:

        Pecan and a pecan containing cookie (Malanin et al. 1995 [105]).

      • Protocol: (controls, definition of positive etc)

        Prick-Prick, moistening the pecan with saline. 10 mM histamine dihydrochloride was the positive control.

      • Number of Patients:Malanin et al. (1995) [105] tested one patient.
      • Summary of Results:

        Malanin et al. (1995) [105] found that the patient reacted only to the cookie or pecan nuts from the cookie (5x5mm) rather than to raw pecan.

      IgE assay (by RAST, CAP etc)

      • Number of Studies:0
      • Food/Type of allergen:

        Malanin et al. (1995) [105] extracted fresh, heated and stored pecan nuts with 150 mM NaCl and 3 mM NaN3 (1:10, w/v) and coupled to CNBr-activated filter paper disks.

        Sicherer et al. (1998) [517] used a commercial extract.

      • IgE protocol:CAP
      • Number of Patients:111
      • Summary of Results:Sicherer et al. (1998) [517] report that 11/111 patients who reacted to pecan had a mean specific IgE of 18.3 kU/l while 10/111 peanut or tree nut allergic patients who had eaten pecan without a reaction had a mean pecan specific IgE of 1.6 kU/l.


      • Immunoblotting separation:

        Immunoblotting is only described in a preliminary report (Teuber SS, Sathe SK, Roux KH, Peterson WR. J. Allergy Clin. Immunol. 105 (1), S424).

      • Immunoblotting detection method:
      • Immunoblotting results:

      Oral provocation

      • Number of Studies:0
      • Food used and oral provocation vehicle:
      • Blind:
      • Number of Patients:
      • Dose response:
      • Symptoms:No oral provocation performed

      IgE cross-reactivity and Polysensitisation

      Sicherer et al. (1998) [517] report that pecan is the second most common tree nut allergy in peanut allergic patients after walnut (13 pecan allergic/54 tree nut allergic/102 patients). Roux et al. (2003) [694] and an abstract (Teuber SS, Sathe SK, Roux KH, Peterson WR. J. Allergy Clin. Immunol. 105 (1), S424) report that there is complete IgE cross reactivity by immunoblotting between pecan and walnut.

      Other Clinical information

      Many studies report allergy to "tree nuts". Allergy to pecan was the fourth most common of the tree nuts allergies reported by Sicherer et al. (2001) [826] with 9% of the 1667 nut allergic registrants reporting pecan allergy. Similarly Sicherer et al. (1998) [517] report 13/54 nut allergic patients as pecan allergic. However, the symptoms, described as 89% involved the skin (urticaria, angioedema), 52% the respiratory tract (wheezing, throat tightness, repetitive coughing, dyspnea), and 32% the gastrointestinal tract (vomiting, diarrhoea) were not associated with specific nuts. In the UK pecan may not be as common a source of tree nut allergy with Clark and Ewan (2003) [615] reporting 8/1000 patients showing their strongest reaction to pecan based on clinical history (however, the number of patients who tolerated pecan was not reported).

      Malanin et al. (1995) [105] and Berrens (1996) [24] report a neo-allergen, which appears on storage (>2 weeks) of pecan nuts and products containing nuts. They suggested that a Maillard reaction product might be the allergen.

      Reviews (1)

      • Roux KH, Teuber SS, Sathe SK.
        Tree nut allergens.
        Int Arch Allergy Immunol. 131(4):234-244.. 2003
        PUBMEDID: 12915766

      References (8)

      • Roux KH, Teuber SS, Sathe SK.
        Tree nut allergens.
        Int Arch Allergy Immunol. 131(4):234-244.. 2003
        PUBMEDID: 12915766
      • Clark AT, Ewan PW.
        Interpretation of tests for nut allergy in one thousand patients, in relation to allergy or tolerance.
        Clin Exp Allergy 33(8):1041-1045.. 2003
        PUBMEDID: 12911776
      • Sicherer SH, Burkes AW, Sampson HA.
        Clinical features of acute allergic reactions to peanut and tree nuts in children
        Pediatrics 102 1-6. 1998
        PUBMEDID: 9651458
      • Sicherer SH, Furlong TJ, Munoz-Furlong A, Burks AW, Sampson HA.
        A voluntary registry for peanut and tree nut allergy: characteristics of the first 5149 registrants.
        J Allergy Clin Immunol. 108(1):128-32.. 2001
        PUBMEDID: 11447394
      • Malanin K, Lundberg M and Johansson SGO
        Anaphylactic reaction caused by neoallergens in heated pecan nut.
        Allergy 50: 988-991. 1995
        PUBMEDID: 8834830
      • Yunginger JW, Sweeney K, Sturner WQ, Giannandrea LA, Teigland J, Bray M, Benson PA, York JA, Biedryczki L, Squillace DL
        Fatal food-induced anaphylaxis.
        JAMA 260:1450-1452.. 1988
        PUBMEDID: 3404604
      • Gillespie DN, Nakajima S, Gleich GJ
        Detection of allergy to nuts by the radioallergosorbent test.
        J Allergy Clin Immunol 57:302-309.. 1976
        PUBMEDID: 1262606
      • Berrens L
        Neoallergens in heated pecan nut: products of Maillard-type degradation?
        Allergy 51: 277-278.. 1996
        PUBMEDID: 8792931