Thank you for your inquiry.
There is indeed a small body of scientific literature documenting a cross reactivity between allergens found in latex and chemicals found in poinsettia. The clinical significance of this cross reactivity, however, has not been clearly established. There is a nice analysis (in lay terms) of this issue released by The American Latex Allergy Association and written by Dr. Kevin J. Kelly, who is an expert in latex allergy.
In addition, there is also a press release from the American College of Allergy, Asthma, and Immunology summarizing a presentation by Dr. Peter M. Ranta delivered at an annual meeting of the College. I have copied the press release for you below:
“Allergic to Latex? Poinsettia Plants May Pose Risk
Source: American College of Allergy, Asthma and Immunology (ACAAI)
Newswise — Individuals with latex allergy should be cautious around poinsettia plants, since exposure may result in a severe allergic reaction, according to preliminary research findings presented by Peter M. Ranta, M.D., Augusta, Ga., at the recent Annual Meeting of the American College of Allergy, Asthma and Immunology (ACAAI) in New Orleans.
The ornamental poinsettia plant (Euphorbiaceae), popular during the Christmas holiday season, is part of the same plant family as natural rubber latex (NRL), which is obtained from the Brazilian rubber tree (Hevea brasiliensis). Dr. Ranta and colleagues found two cross-reactive proteins in poinsettia extracts that correspond to proteins in natural rubber latex.
Dr. Ranta was able to pinpoint the allergenic proteins by extracting plant fluid from the poinsettia and mixing it with blood drawn from subjects sensitive to NRL. Of the latex sensitive sera, 40 percent (6/15) had poinsettia specific IgE, a blood protein indicative of an allergic reaction. The blood was later evaluated to pinpoint the common proteins prompting the allergic reactions using immunoblot inhibition. The technique permits scientists to separate proteins from a blood by blotting it on paper that can capture the different sized proteins at different heights of the sheet. Electricity causes the proteins to separate and migrate up the film. He used the pooled serum with IgE specific to both NRL and poinsettia and switched off allergen binding by poinsettia and NRL extracts. Through process of elimination he was able to define Hev b 6.01 and Hev b 10 as the common allergenic denominators between the two sources.
The ACAAI is a professional medical organization, headquartered in Arlington Heights, Ill., comprised of 4,963 qualified allergists-immunologists and related health care professionals. The College is dedicated to the clinical practice of allergy, asthma and immunology through education and research to promote the highest quality of patient care.”
The American Latex Allergy Association statement by Dr. Kelly was evidently given in response to several scientific articles appearing in the medical literature. There was Dr. Ranta’s presentation noted above. In addition, there have been descriptions of allergic reactions to poinsettia and an analysis of the cross reactivity between latex and the contents of poinsettia. A few of these references and abstracts are copied for you below.
In summary, there is some amount of evidence that poinsettia can cause allergic reactions and that these reactions may be due to allergens which cross react with latex. However, as noted in the analysis by Dr. Kelly (the link to which is given above), the true significance of this phenomenon is unknown, and cases potentially related to such cross reactivity, at least at this time, appear to be very rare.
Thank you again for your inquiry and we hope this response is helpful to you.
Allergy. 2004 Oct;59(10):1127-8. Asthma induced by latex from 'Christmas flower' (Euphorbia pulcherrima). Ibáñez MD, Fernández-Nieto M, Martínez J, Cardona GA, Guisantes J, Quirce S, Sastre J.
Source: Hospital Universitario Niño Jesús, Av. Menendez Pelzyo 9, 28009 Madrid, Spain. firstname.lastname@example.org
J Pharm Sci. 1967 Sep;56(9):1184-5 contd.
Chemical study of the latex, stems, bracts, and flowers of "Christmas Flower" (Euphorbia pulcherrima). I. Dominguez XA, Garcia Delgado J, De Lourdes Maffey M, Mares JG, Rombold C.
Journal of Allergy and Clinical Immunology Vol. 111, Issue 2, Supplement, Pages S380-S396
Rhinitis and Asthma Induced by “Christmas Flower” (Euphorbia Pulcherrima)
M. Ibañez-Sandin 1, M. Fernández-Nieto2, J. Martinez3, S. Quirce2, J. Sastre 2; 1Allergy, Hospital Niño Jesus, Madrid, SPAIN, 2Allergy, Fundacion Jimenez Diaz, Madrid, SPAIN,
3Pharmacia Diagnostics, Barcelona, SPAIN.
Rationale: Christmas flower or Poinsettia (Euphorbia pulcherrima (Ep)) belongs to Euphorbiaceae family as Hevea brasiliensis (Hb). We studied a 6-year-old male that presented rhinitis and asthma when exposed to Christmas flower for two consecutive seasons.
Methods: The antigenic and allergenic profiles of extracts of leaves and latex from Ep were evaluated by skin prick tests (SPT), SDS-PAGE and immunoblots, and cross-reactivity by ELISA inhibition.
Results: SPT with Ep extracts and grasses were positive. Total IgE was 703 kU/L, specific IgE was positive for Ep extracts (65 kU/L), latex from Hb (8.45), rHeb b5 (8.24), banana (6.28) and chestnut (9.3). IgEimmunoblot analysis demonstrated bands of 69, 60, 44, 40, 36, 25 and 19 kDa, the most intensive reaction being the one corresponding to the to 36 kDa bands which is Heb b5. Ep extract induced an intense inhibition of CAP with latex from Hb. Baseline methacholine PC20 was 14.3 mg/ml and baseline induced sputum demonstrated no eosinophils. Specific Bronchial challenge test with Ep extract elicited an immediate fall in FEV1 of 20%. Twenty four hours after it methacholine PC20 decrease to 2.5 mg/ml and eosinophil were seen in induced sputum. Rubbing and glove test use with latex from Hb were negative. Five out of 8 patients allergic to latex had positive skin test to Ep extracts.
Conclusions: This is the first description of rhinitis and asthma induced by sensitization IgE-mediated to Ep. Although, cross-reactivity to latex and sensitization to banana and chestnut were evident, the patient was able to tolerate them.
Poinsettia Plants Pose Allergy Risks
Southern Medical Journal 2006 Jul;99(7):772-3.
No poinsettia this Christmas.
Bala TM, Panda M.
Department of Medicine University of Tennessee College of Medicine Chattanooga Unit, Chattanooga, TN 37403, USA.
Poinsettia is one of the most delightful decorations during the Christmas season. Natural rubber latex and poinsettia share some common allergen proteins. Hence, people with latex allergy may develop cross-reactivity with poinsettia. We report the case of a 50-year-old white female with a history of latex allergy, who developed a skin rash due to exposure to the poinsettia plant. The patient was admitted to the hospital for evaluation of near syncope. Her diagnostic workup was normal. She received a poinsettia plant from a friend during hospitalization. Because of her latex allergy, we carried out an extensive research of literature which revealed a cross-reactivity between latex allergy and poinsettia. The rash responded well to systemic antihistaminic treatment and removal of the plant from the room.
Phil Lieberman, M.D.