Eczema is a chronic itchy skin condition of multi-factorial origin. The underlying cause is a disrupted skin barrier usually due to genetic causes. Many factors can aggravate eczema such as heat, sweating, illness, irritants, and in some cases, certain foods.
It is a common misconception that eczema is usually caused by food allergies. Indeed food allergies are far more common in eczema patients than in patients with a normal skin, but usually not the “cause” of eczema. Up to 40% of patients with moderate to severe eczema have a food allergy of sorts, most commonly to egg, peanut and cow’s milk. However, in less than 20% of cases does ingestion of these foods actually lead to the eczema. More commonly, these foods cause a typical immediate reaction in eczema patients, such as immediate hives and rashes, and maybe even more severe reactions such as breathing difficulties. In the minority of eczema patients such foods actually cause eczema flares. Certainly, blanket elimination diets are not to be used in eczema patients. Unnecessary elimination of vital foods can lead to nutritional complications and is socially difficult. Of course, it is of vital importance to identify true food allergies as ingestion of the offending foods may cause potentially dangerous reactions. Therefore, if the patient or clinician is concerned about food allergy in eczema, rather have a proper assessment by an allergist, who can determine exactly which foods may be involved.
Interestingly, although many people believe that food allergies cause eczema, which we have now learned occurs in the minority of patients, it is true that the opposite relationship is more common: eczema can cause food allergies. This is because a broken skin barrier can let allergens through the skin and set up an immune response which can lead to allergies. Therefore, effective treatment and prevention of eczema is an important step in food allergy prevention.