Poets and philosophers long have argued chicken/egg algorithms. And scientists have argued food allergy/eczema scenarios. For years it was felt food allergy was the seminal event preceding eczema.
The natural history and logic of this position are hard to dismiss. Even a 5-year-old who recently completed his allergy testing to better understand his skin rash, (which showed strong positives to both egg white and egg yolk), asked me why he needed to have these tests for his “eggs-ema.” Wasn’t it obvious to the doc that eggs were the cause?
As it turns out, it’s the eczema that causes the food allergy. Or actually in more technical terms, it’s the loss in skin-barrier function that causes food allergy. The primary fault in eczema is a less-than-ideal barrier response of the skin, due to reduced production of a barrier protein called filaggrin. This allows skin absorption of food, which in turn leads to the development of food allergy. The loss of barrier function antedates the actual appearance of the eczema rash.
Ironically, once the food allergy develops, it becomes a strong driving force to worsen the eczema.