Food Allergies

H. Farhadian, M.D., F.A.A.P., F.A.A.A.A.I.
Copyright© 2019, H. Farhadian, MD. All rights reserved.

Adverse Reaction to Food

By definition, an adverse reaction to food or food additives is, any unusual reaction that occurs after consumption and ingestion of a food. These reactions include allergic, enzymatic, idiosyncratic or chemical.


Statistics have shown that one out of every three individuals has experienced some type of unusual reaction to certain foods. However, only five to seven percent of Americans suffer from a true food allergy.


Within a few minutes to several hours after ingestion, allergic symptoms that may develop include itching of the mouth and lips, and swelling of the lips, tongue, face and throat. Also, nausea, vomiting, diarrhea and skin rash may occur. In several cases, food allergy may lead to low blood pressure and anaphylactic shock, which can even be fatal. Sometimes food allergy can be manifested by respiratory symptoms, such as runny nose and wheezing.

The most common questions asked about food allergies are as follows:

Question: What are the most common food offenders?

Answer: Peanuts, tress nuts, egg, sea food, milk, wheat and soybean.

Question: How about chocolate and sugar in children?

Answer: In a study on 60 children who were complaining of being allergic to chocolate, none turned out to be truly allergic through a double placebo control study. The same is true about sugar.

Question: What food is the most dangerous one to be allergic to?

Answer: Peanuts. Usually a reaction happens after ingestion of 50 to 100 gm of a certain food. However, in the case of peanuts, only a few mg (5-10) could lead to severe systemic reaction. Even smaller amounts such as 50-100 mcg means 1:10,000 gm might cause transient allergic reaction.

There have been cases reported due to the opening of a can of peanut butter and smelling peanuts. Using a knife that was contaminated with peanut butter has also been responsible for significant allergic symptoms.

Question: How do you diagnose food allergy?

Answer: The old standard of diagnosis is a Double Blind Placebo Controlled Food Challenge (DBPCFC). However, history and skin tests by food antigen, especially fresh food, are helpful.

Question: What is advised for those patients or parents of the children who suffer from food allergy?

Answer: Diagnosis should be established by an expert specialist. After establishing a diagnosis, the key is avoidance.

A) Read all labels and list of ingredients, but do not have 100 percent faith in them.

B) Preferably, eat at home and limit eating at restaurants to a minimum.

C) Always carry an emergency kit with you. As soon as you realize that you ingested an allergic food that might cause anaphylactic reactions, use an injection of epinephrine (one called epipen). Also, oral use of 25-50 mg of Benadryl capsule or preferably liquid will be helpful. You still need to go to the closest medical facility (emergency room) and stay for a few hours to make sure that anaphylaxis won't occur or reoccur. The recurrence of anaphylaxis, even up to 36-48 hours after initiation is possible. In case anaphylactic reactions happen, first call the paramedics. Then carry out the above measures. In the meantime, the patient must be positioned on a flat surface and a free airway established to allow him/her to breath.

Question: Is there any type of cure available such as immunotherapy or allergy shots for food allergy as is for inhalant allergies?

Answer: Unfortunately, this method could be dangerous and not effective at this time. However, in some other countries, it still is in use. If we could find an antigen that is immunogenic but not allergenic, ti would be ideal for this purpose.