Many of the ways a food allergy or food intolerance manifest in the body happen to be the same but there is a difference between a food allergy and a food intolerance.  The difference is that a food allergy triggers a measurable immune system response while a food intolerance does not. A food intolerance causes upset of the natural processes of the gut to the degree that symptoms will start to show both in the gut such as cramping and bloating to the more extreme leaky gut whose permeability has changed, to symptoms in other body tissues such as eczema of the skin.