By Kevin J. Kelly, MD
At this time of year we receive many phone calls regarding the potential for patients who have natural rubber latex allergy to develop allergic reactions to poinsettia plants. Fortunately, I do not recall seeing or hearing of any severe allergic reactions to poinsettia contact in our patient's who have latex allergy. There are multiple lactifer or latex secreting plants in the world. Poinsettia is one of the most common flowering tropical plants. It comes from the family Euphorbiaceae of which Hevea brasiliensis (the rubber tree) is a member.
A small table is included at the end of the text of some plants related to the Hevea brasiliensis. Little is published on this cross reactivity of latex in this family in the medical literature. However, early in the 1990's our research group spent some time and effort on characterizing some cross reactivity between the latex derived from poinsettia and from Hevea brasiliensis. There appears to be cross reactivity in the laboratory setting of the latex proteins from these plants. Most important though, one would have to have significant contact with the poinsettia plant's latex directly to have an allergic reaction. Otherwise, a high number of reactions would be reported in the population of patients who have latex allergy. The latex is found in a circulation system within the plant and is not secreted until the system is accessed by breaking a leaf or injuring the plant in some manner. Even in this case, only a small drop of latex that can be immediately wiped off of the skin is unlikely to cause an allergic reaction. Despite this minimal risk, we are discouraging direct contact with poinsettia latex because of the remote possibility of an allergic reaction.
It would be prudent not to overreact to the mere presence of poinsettia in the environment, as this is likely to be safe.
For those who wish to avoid all forms of latex as recommended by their doctors, their personal contact with poinsettias should be limited.
|Hevea brasiliensis||Rubber Tree|
|Euphorbia splendens||Crown of Thorns|
|Acalypha wilkesiana||Jacobs Coat|
|Ricinus communis||Castor Bean|
|Acalypha hispida||Chenile plant|
Dr. Kelly is Professor of Pediatrics/Medicine and Chief of Allergy &
Immunology at the Medical College of Wisconsin.