"Do I have chocolate allergy?" is not an uncommon question.According to the current guidelines however, chocolate allergy is extremely rare.
The practice parameter for food allergy postulates that since the proteins of cacao nut undergo extensive modification into relatively nonallergenic complexes during the processing of commercial chocolate, clinical sensitivity to chocolate is vanishingly rare.
Chocolate allergy vs. pseudoallergy
Most allergists have never seen a patient with "true" chocolate allergy. There is only one article in Pubmed about chocolate allergy from 1971. It was contradicted a few later by a second review which emphasized on chocolate pseudoallergy.
Allergy to contents of a chocolate bar
Symptoms of "chocolate allergy" could be due to allergy to any of the following:
- milk
- tree nuts
- peanuts
- soy
- cockroach - up to 60 insect parts per 100 gm bar are considered "acceptable"
Adverse reactions to pharmacological agents
Adverse reactions after chocolate consumption could be due to pharmacological agents normally present in chocolate such as theobromine (chocolate, tea) and phenylethylamine (chocolate).
Table 1. Differential diagnosis of adverse food reactions (Adapted from Sampson. J Allergy Clin Immunol 1986; 78:212–219.)
Pharmacologic agents
Caffeine (coffee, soft drinks)
Theobromine (chocolate, tea)
Histamine (fish, sauerkraut)
Tryptamine (tomato, plum)
Serotonin (banana, tomato)
Phenylethylamine (chocolate)
Tyramine (cheeses, pickled herring)
Glycosidal alkaloid solanine (potatoes)
Alcohol
Psychological reactions - food aversions, food phobias, etc.
The recently launched "allergy-friendly" chocolate bars "boom CHOCO boom" are called so because they are supposedly the first dairy-, nut- and soy-free chocolate bars, not because they do not contain cacao products.
Common allergens
8 foods cause 90% of food allergies (TEMPS WFS) (click to enlarge the image). The likelihood of a negative oral food challenge is shown in relation to the respective values of skin prick test (SPT) and serum IgE (sIgE). See more Allergy and Immunology mind maps here.
References
Food allergy: a practice parameter. American College of Allergy, Asthma, & Immunology. Food allergy: a practice parameter. Ann Allergy Asthma Immunol 2006 Mar;96(3 Suppl 2):S1-68. [682 references].
"Allergy-friendly" chocolate bars?
"Chocolate Allergy" is actually due to cockroach in chocolate - up to 60 insect parts per 100 gm bar "acceptable". ABC News, 2012.
Food Allergy: A Short Review. Allergy Cases.
Chocolate from Wikipedia, the free encyclopedia
Chocolate allergy: a double-blind study. Maslansky L, Wein G. Conn Med. 1971 Jan;35(1):5-9.
Case in point: allergy, intolerance or pseudoallergy to chocolate? [Article in French] Riv Eur Sci Med Farmacol. 1989 Jun;11(3):247-9.
http://en.wikipedia.org/wiki/Theobromine
http://en.wikipedia.org/wiki/Phenethylamine
Flavored Coffee May Trigger Seasonal Allergies - due to oral allergy syndrome. Fox News, 2011.
Image source: Wikipedia.
Comments from Twitter:
@DoctorMac: Currently skin testing a patient to chocolate. Must use varying contents of cocoa. Also must perform frequent quality control testing. Perhaps surprising no one, all tests were negative. The oral challenge went equally well, patient, M.D. & nurse all tolerated it fine.
Comments regarding cockroach parts in chocolate:
Rach @designbyday: Ew RT @DrVes: "Chocolate Allergy" is due to cockroach in chocolate - up to 60 insect parts per 100 gm bar "acceptable" j.mp/HJ6IzF
Linda Pourmassina,MD @LindaP_MD: why do you do this to me? This is one time I might say ignorance is bliss.
Eladio Ramos @eladio_ramos: Gid! That's April fool, isn't it?
Greg Smith MD @GregSmithMD: That's it. Life is over.
Dr. Ellis @DrAnneEllis: still so helpful to know: Chocolate Allergy often due to cockroach-<=60 insect parts per 100 g "acceptable" j.mp/HJ6IzF
Francis Lam @Francis_Lam: Fabulous! I mean, have you ever seen the FDA guidelines? They're kind of hilarious:
http://www.salon.com/2011/01/27/fda_food_defect_action_levels/
http://www.fda.gov/food/guidancecomplianceregulatoryinformation/guidancedocuments/sanitation/ucm056174.htm
Dr John Weiner @AllergyNet: So, chocolate contains cockroach parts. Will "May Contain Traces Of Cockroach" be the next allergy warning?