Chocolate Allergy? It's Vanishingly Rare

"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)

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.


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.
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"

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"

Francis Lam @Francis_Lam: Fabulous! I mean, have you ever seen the FDA guidelines? They're kind of hilarious:

Dr John Weiner @AllergyNet: So, chocolate contains cockroach parts. Will "May Contain Traces Of Cockroach" be the next allergy warning?


  1. I would be very interested in what you and your colleagues do to determine if a stated "allergy" is really an allergy. Many times I'll have patients who describe nausea following antibiotic administration as an allergy. Other patients will claim they are allergic to "all 'cillins'" (which from my perspective seems unlikely because cillin is not an antigenic determinant.

    In the early 90s I did a series of penicillin desensitizations for pregnant patients with syphilis and stated penicillin allergy.

    Skin testing revealed that 30% did not have an allergy although they were certain that they did... I'll always regret the fact that I never published that study.

  2. Dear Dr. Onyeije,

    Thank you for your comment.

    Drug allergy is a variable state and in the case of penicillin allergy, 85% of patients who give a history of a previous reaction to penicillin will tolerate a course of penicillin at a later stage. History is not very reliable when diagnosing PCN allergy.

    If more than 2 years have elapsed since a previous reaction, skin testing could be performed to confirm ongoing sensitivity but the skin test antigens are currently unavailable.

    Nausea is not a typical presentation of PCN allergy.

    Clinical presentation can be remembered by the mnemonic MAUS:

    Maculopapular exanthema, 19.1%
    Anaphylaxis without shock, 19.1%
    Urticaria, 36.7%
    Shock, anaphylactic shock, 17.6%

    1. ALLERGY NOTES: .....

      Please respond if you can to this question..

      I have been to several doctors, allergy, endo etc you name it and none have been able to help me. I suspect myself that my body is reacting on a neurological level to caffeine, however it seems COCOA has a more potent affect on my body, perhaps because of the heart stimulating properties.

      I have mitral valve prolapse and regurgitation. acid reflux, gastritis, blood sugar issues (however probably from the gastritis, though confirmed OGTT test - Reactive hypoglycaemia *

      Now, basically whenever I have tea / coffee / or Cocoa ;
      (I believe they all have similar chemicals) ? ... ,

      .. I get the most Severe reaction. I have excluded panic attacks or anxiety disorder due to the following:

      1. I have a masters in psychology.
      2. I am a calm person with a notable relaxed demeanour and have been known to remain calm in excitable /risky / dangerous situations.

      3. most importantly, I've never experienced anything akin to these episodes without the ingestion of said foods.

      Now, the first time this occured, this was a severe reaction, convulsion / seizure-like in nature. Including a heart-rate I could not physically count (I except higher than 250bpm), termbling, all over pins and needles/ flushing, including in the face and eyes. My extremities turned blue and locked up, perhaps due to hyper ventilation, though similar has happened at a subsequent episode without hyperventilation (which has baffled me even further) !

      The feelings also involve extreme nausea, and a feeling of needing to throw up and pass out simultaneously.

      Strangely this feeling is present for about 10 minutes before it hits the peak (rapid heart rate and what I would describe as physiological shock) , with the nausea and feeling to evacuate my bowls existing for about 1 hour prior.

      The timing of these episodes of tea/coffee/chocolate ingestion varies however..
      For example, it can be quick, all within 2 hours, or lasting for 2-3 hours before it get's to the peak. Of course with the after effects being felt for DAYS * though on occasion after 1 day I was fine, others required 3+ days of recuperation. Perhaps due to the stress on my heart I am not sure.

      For reference, I am mid twenties, male, less then adequate physical health for my age due to poor sleep and no exercise.
      This has reminded me. Exercise can cause this response too, however, usually due to not eating, or eating too much, or eating certain foods.

      I have no idea why this is *

      If you have any ideas, perhaps a certain chemical/neurotransmitter / lactic acid etc. is causing this, please reply!

      Thank you.

  3. chocolate allergy? that is lol. never heard that before. u have chocolate in almost every kind of cake. that is sad

  4. Anonymous7/10/2009

    It's actually a quite common question and there is nothing to laught about it, Lisa, especially not "lol"...

  5. Anonymous7/18/2009

    Glad to hear it's rare. Even so, I had a chocolate allergy when I was young. Caused eczema on my thighs and arms. Got progressively worse through high school. It got so bad I had to wear long sleeves everyday year round. Treatment consisted of some kind of gooey, gell that I put on at night covered by saran wrap held on by tape--not comfortable or effective (this was in the 70's). I was covered in those days by the military healthcare system as a dependent & it took a year of "treatment" before I was authorized to see an allergist off base. He took one look at it, said don't eat chocolate or nuts for 3 weeks & come back if it doesn't go away. It did! Within a few years, I started experimenting with eating nuts (no problem) or my mother's chocolate cake (eczema returned). Sometime in my twenties, when I tried chocolate again, no reaction & I have been eating it since. I've since read that food allergies can come and go for no apparent reason. I certainly hope it doesn't come back. Is it likely? Also, seems like I'm developing a sensitivity to peanuts, so have been avoiding them under the theory that it could become a new allergy. (I have a nephew who goes into anaphylactic shock from any contact with peanuts, and we both have pollen allergies.)

  6. Anonymous7/11/2012

    i have a true cocoa allergy, after trying to find out info on the internet about it can now see why everytime i see a new allergic they retest me for it. and they are always suprised when it comes back that im allergic to it. yet that is how i found out i was allergic to it when i was 16. i have never liked chocolate it always made me ill, but i never would have guessed im one of those rare people who are allergic to it.

  7. Anonymous8/12/2013

    I am allergic to Chocolate. I developed an extreme sensitivity to it when I was in my early 20's. I don't have any of the 'normal' symptoms. Quite simply I start to bleed in my stomach and then it rapidly spreads to other organs, until I am bleeding from almost every orifice. It's horrific. All it takes to trigger a mild reaction (crippling stomach-ache) is a chocolate digestive biscuit. 2 blocks from a milk chocolate bar causes full blown bleeding for 2 or 3 days. I have no reaction to any other foodstuff. I've been caught out in restaurants - Mexican food particularly I have to avoid after crippling myself once eating a chicken dish - although the chef was very impressed I was able to state with absolute confidence that there was chocolate in the sauce as it was one of over 50 ingredients and unlisted on the menu.


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