Do I Have a Food Allergy?

You might think that gastroenterologists like me are conversant with food allergies.  You would be wrong.  Here is a second misunderstanding you likely harbor.  Most individuals who believe or suspect that they are suffering from a food allergy have no allergic condition at all.  A true allergic reaction involves the firing off of one’s immune system in response to an external stimulant resulting in a rash, wheezing and other characteristic allergic responses.  Poison ivy, for example, is an allergic reaction.  Nausea resulting from an antibiotic is not an allergic reaction. 

Physicians, of course, appreciate this distinction.  This is why when you tell us you are ‘allergic’ to a medication, we will ask you specifically what the reaction was.  In my experience, most of these ‘allergic reactions’ are routine non-allergic side effects. 

Often enough, a patient will claim to have a penicillin allergy, for example, but has no clue what the reaction might have been. 

True food allergy is rare.  In contrast, food intolerance, such as to lactose or fructose, is much more common and often mistakenly referred to by patients as a food allergy.  (As an aside, most individuals who suspect that they are lactose intolerant are shown not to have the condition when they are formally tested for this disorder.)

 Is there an udder explanation for your 'allergy'?  

Every week, I see patients before me inquiring about various, suspected food intolerance.  How do we physicians begin to sort through this murky morass?  

I have learned to respect patients’ knowledge of their bodies, even if it may not make rational medical sense.  If a reasonable person makes a reasonable assertion, then I give it a fair hearing, even if the claim has not been substantiated scientifically.  For example, if a person has observed that every time he dips into guacamole he develops a pounding headache, should my response be, ‘it’s all in your head’, since this condition hasn’t been published?  Not only is such a response arrogant, but it is also an effective method for pruning one’s medical practice.

Of course, I am not quite as tolerant of a patient’s claim of intolerance if their symptoms are erratic and inconsistent.  For example, if a patient claims to suffer a severe case of lactose intolerance, because milk in their morning cereal causes cramps, but ice cream is gulped down with gusto, then I will issue a ruling of Not Guilty to the maliciously accused Lactose defendant. 

If I suffered from lactose intolerance, then I would face a true conundrum.  Most of my days begin and end with ice cream.   Perhaps, I’m not the best doctor to offer nutritional advice.