Increased intestinal permeability to food proteins explains the whole body effects of food allergy. The association of Crohn's and celiac disease, for example, with psoriasis and arthritis suggests that increased uptake of food antigens from the digestive tract can be the mechanism of systemic inflammatory disease.

The absorption of short-chain peptides derived from food has profound biological significance since receptors to peptides abound in the body and peptides of about 9 amino acids and longer can act as antigens. Great numbers of different peptides can be produced by digestion.

Food protein antigens make their way through human bodies in a remarkable fashion. Every tissue of the body can host a food allergic response. Some activity is noticed in minutes; usually the onset is delayed hours to days.

Manifestations include whole body symptoms such as flushing, fever, aching, fatigue, and also localized target organ activity, usually some form of inflammation, felt as pain, swelling, redness and local heat.  

Page 4 of the Food Allergy Tutorial...