The Man With Recurrent Leg Swelling

 Saw an interesting case last week.

Thirty-two year old Caucasian man, works loading-unloading shlelves in a supermarket. Over several months, has had recurrent episodes of swelling in his right lower foot, extending from shin, across the ankle into the dorsum of foot. During the episodes, which last several hours, the leg feels very swollen, tight and uncomfortable but not much actual pain.

As usual GP thought of gout, checked urate levels- plumb normal. Does a MRI of the ankle after a normal X-ray. That just shows subcut fluid, joint looks fine. Inflammatory markers normal.

Chap comes to Rheumatology clinic. I get a bit more history. Turns out that the episodes always happen after lunch when he goes back to his rather manual role at the supermarket. He usually has various types of sandwich for lunch.

Has he ever had anything else that seemed unusual? Turns out that in the past, on several occasions, when he had a can of Fosters (a type of lager), his throat felt swollen "inside", so that he would struggle to swallow for hours afterwards, although there was no shortness of breath. He now avoids lager.

The penny drops. The guy has a fascinating condition called "Food Dependent, Exercise Induced Anaphylaxis" (FDEIA). Most published cases in the literature have been in conjunction with wheat consumption, followed shortly afterwards by exercise. Except that now we realise that it's not just exercise, but alcohol and NSAIDs that can trigger this after subjects have fed.

Although in most cases, the putative food contains wheat, other allergens that can trigger it are celery, mustard, fenugreek and coriander. Celery and mustard are of course widely added to spice up pizzas and other takeaways and therefore may be hidden.

You might have guessed that the episodes of "swelling" inside the throat and the leg, both represent angioedema, the first mucosal, the second cutaneous.

This is now called augmentation factor anaphylaxis or cofactor associated food allergy. Avoidance works best, but of course, sometimes the specific food trigger can be hidden, and therefore difficult to identify.

Interestingly celery interacts with birch pollen and a couple of other pollen to give rise to what is described as "Pollen Food Allergy". These people with apparent hay fever, get anaphylaxis type episodes every time they ingest celery.

Such people sgould avoid food that contain a very high concentration of fruit pulp such as smoothies, as the latter is apparently rich in something called Lipid Transfer Protein (LTP), which is very allergenic.

They should also consider carrying an EpiPen, just in case...