Q:

2/28/2013
Our question involves a patient having nausea and heartburn episodes after eating. These do not occur with each meal which has made it more difficult to identify a certain food responsible. She does have a diagnosed history of tree nut allergy- specifically cashews. Symptoms included hives, throat swelling and itching. She was not avoiding all tree nuts prior to her visit at this office. After skin testing and RAST testing showed multiple positive reactions to all of these including peanut and tree nuts she began avoiding all these foods. The problems come with other positive results on RAST but negative skin testing. Those other than peanut and tree nut with elevated results include: corn (7.86), wheat (11.50), oats (8.97), soybean (6.81) and sesame (2.76)- negative being <0.35. Both eggs and milk were completely negative.

She is feeling better since completely avoiding tree nuts. The residual symptoms are occasional nausea and heartburn. It was suggested to the patient that she keep a food diary which would include foods eaten and any symptoms experienced at that time. Are there any other suggestions for this patient? Thank you for your time.

A:

Thank you for your inquiry.

As you are well aware, the presence of specific IgE to a food does not mean that the food is causing symptoms upon ingestion. The only true test for food allergy is an oral challenge. Unfortunately, there are difficulties, as you might guess, in performing oral challenges to these many foods, especially when the endpoint is not a visible one (nausea and heartburn). There are so many other factors that might be considered as causes of nausea and heartburn that even a positive response would be difficult to interpret.

Nonetheless, to assess any definitive relationship between the ingestion of a particular food and the symptoms expressed, an oral challenge would be needed. Because nausea and heartburn can also be aggravated by psychological factors, a blinded food challenge would be the preferred technique. However, as noted, from a practical standpoint this would be difficult.

Another technique that is used to diagnose food allergy is a food diary, as you have already instituted. However, from personal experience, I do not think that will be an effective tool for you in this particular patient.

Empiric withdrawal of foods from the diet is the final technique that you could employ, and I think this would be easier and more effective than a food diary.

Finally, I believe this patient, if they have not seen a gastroenterologist, should do so. There are other diagnoses that clearly need to be considered, and the patient might benefit by an EGD with an esophageal biopsy.

Thank you again for your inquiry and we hope this response is helpful to you.

Sincerely,
Phil Lieberman, M.D.




AAAAI - American Academy of Allergy Asthma & Immunology