There are two issues to consider in response to your question. The first issue is whether or not someone allergic to other tree nuts would react to coconuts, and the second is whether or not a person allergic to coconut would react to coconut oil.
The first issue can be viewed from two perspectives. The first perspective is whether or not a reaction to coconut in a tree nut allergic patient would be due to cross-reactive allergens between coconut and other tree nuts. Clearly cross-reacting allergens have been demonstrated (1, 2) and thus there is a potential for cross-reactivity due to the presence of such allergens.
The second perspective is whether or not a person allergic to one nut would be, because of their genetic predisposition, more likely to react to another nut. The answer to this question is yes. For example, we know that patients allergic to peanuts are more likely to be allergic to tree nuts than someone in the general population as a whole. This is because people who are allergic to foods oftentimes demonstrate allergy to multiple foods even though there are no cross-reacting allergens within the two foods.
So, based upon these observations, the child you described would be at increased risk of being allergic to coconut. However, such risk is probably slight since coconut allergy per se is reasonably rare.
The second issue is whether or not a person allergic to coconut would react to the oil. We have dealt with that question previously on our website, and for your convenience, I have copied the question and our response below. As you can see from this response, it would be very rare to react to coconut oil, but there is one recorded case in the literature and therefore, we could not rule out, should this child be allergic to coconut, a possible reaction to the ingestion of coconut oil.
In summary, I think it highly unlikely that this child would react to coconut oil, but could not rule out that possibility based upon the available evidence. With these observations in mind, my suggestion to you would be that the child be evaluated by an allergist-immunologist. We have good tests for allergy to coconut per se, and a negative test would be very reassuring that this child would be able to ingest the oil without difficulty. You can find an allergist-immunologist is your area by visiting our "Find an Allergist / Immunologist" directory.
Thank you again for your inquiry and we hope this response is helpful to you.
1) Teuber SS, Peterson WR. Systemic allergic reaction to coconut (Cocos nucifera) in 2 subjects with hypersensitivity to tree nut and demonstration of cross-reactivity to legumin-like seed storage proteins: new coconut and walnut food allergens. J Allergy Clin Immunol 1999;103(6):1180-5.
2) Nguyen SA, More DR, Whisman BA, Hagan LL. Cross-reactivity between coconut and hazelnut proteins in a patient with coconut anaphylaxis. Ann Allergy Asthma Immunol 2004;92(2):281-4.
Previous inquiry/response on the Ask the Expert website:
Allergy to coconut oil
Should a person with coconut sensitivity avoid coconut oil?
Unfortunately, I cannot give you a definitive answer to your inquiry. I can, however, refer you to articles which discuss this issue, but I am not aware of any study which defines this situation adequately enough to allow us to give you complete assurance one way or another as to whether or not a patient truly sensitive to coconut would react to the ingestion of coconut oil.
What we do know is that coconut allergy per se is very rare. In Paul Hannaway's text (1), which is an extensive review of food allergy, he could only find three documented cases of coconut allergy. I am only aware of one case of a putative reaction to coconut oil (see abstract copied below). The Food Allergy and Anaphylaxis Network (FAAN) collected data on 5,149 patients, and found only 4 individuals who reported allergy to coconut (2). With these small number of cases, it is difficult therefore to come to a conclusion.
There are data on the protein content of coconut oil. Crude oil contains 250 mcg per ml of protein, bleached and filtered oil contains 144 mcg per ml, and if the oil is deodorized, 7.9 mcg per ml (3), but the clinical significance of these figures remains undetermined.
In summary, based upon the available literature, we can only conclude that IgE-mediated reactions to coconut are rare, and that reactions to coconut oil are probably even more so, but because there is at least one reported case, we cannot rule out the possibility of such a reaction in a patient who is truly sensitive to coconut.
Finally, the above response assumes that you were inquiring about IgE-mediated reactions to coconut. Coconut oil is known to be antigenic as far as its predisposition to cause contact dermatitis (see abstract copied below from "Contact Dermatitis"). This can evidently be via an immunologic as well as an irritant mechanism.
(1) Hannaway PJ. On the nature of food allergy. Copyright 2007; Page 111. Published by Lighthouse Press.
(2) Sicherer SH, et al. A voluntary registry for peanut and tree nut allergy: characteristics of the first 5,149 registrants. J Allergy Clin Immunol 2001; 108(1):128-132.
(3) Cravel, et al. Allergenicity of refined vegetable oils. Food and Chemical Toxicology 2000; 38:385-393.
Allerg Immunol (Paris). 1994 Dec;26(10):386-7.
[A case of coconut oil allergy in an infant: responsibility of "maternalized" infant formulas].
[Article in French]
Couturier P, Basset-Sthème D, Navette N, Sainte-Laudy J
The case is presented here of a baby of 8 months fed from her birth with maternal milks. The first milk induced a severe gastro-intestinal disorder which disappeared when a second milk was used. A third milk caused a relapse. The only common allergen was coconut, which was physico-chemically modified in the second milk. Demonstration of the responsibility of coconut oil was based on positive re-introduction tests, positive skin tests for coconut and maternal milk that were negative for cow's milk and peanut and by specific IgE tests which were positive in comparison with negative controls.
Occupational allergic contact dermatitis due to coconut diethanolamide (cocamide DEA)
Volume 29, Issue 5, pages 262–265, November 1993
Coconut diethanolamide (CDFA). manufactured from coconut oil, is widely used as a surface-active agent in hand gels. hand-washing liquids, shampoos, and dish-washing liquids. CD HA has rarely caused allergic contact dermatitis. During NS5 IW2, we investigated 6 patients with occupational allergic contact dermatitis caused by CDEA. 2 became sensitized from a barrier cream, 3 from a hand-washing liquid, and 1 had been exposed both to a hand-washing liquid and to a metalworking fluid containing CDEA. Leave-on products (hand-protection foams) caused sensitization much more rapidly (2 3 months) than rinse-off products (hand-washing liquids: 5–7 years). Due to the extensive use of CDEA and the lack of proper declaration of products, it is difficult to avoid CDEA exposure. No contact allergy to another coconut-oil-derived sensitizer (cocamidopropyl betaine) was found in the patients.
Phil Lieberman, M.D.