All I can say is that the person who finally figures out the relationship between and causes of the symptomatically diagnosed "diseases" of eczema, asthma, and allergies deserves to be made King of the World, at least for a couple of weeks.
As far as I've been able to determine, the current level of medical research just doesn't know what causes these problems to happen. Diagnosis is completely symptomatic. In other words, there is no blood test or definitive metric to say that you have these "diseases", other than the fact that a doctor looks at what's going on and says "yep, it's asthma" or "nope, that's not eczema." In the case of allergies, they can test you by applying the allergen and seeing if you react, but as for why
you react to it, they're pretty much at a loss. These three things, eczema, asthma and allergies, are names given to a set of symptoms, and that is all.
If the medical community wants to impress me, they need to answer to following questions:
Why does an allergy develop? What goes wrong with the immune system, and how can we reverse it? All they can do right now is to mask the symptoms.
What causes asthma to develop, and what is the biological cascade that occurs during an attack? Biologically, what goes wrong with the body that it ceases to be able to perform one of its primary functions? I actually think they may be making some headway with this, as newer drugs attempt to stop the attacks from happening, as opposed to just pelting the patient with steroids and bronchiodialators.
What causes eczema to develop? Ditto all of the questions for allergies.
All of these problems strike (mostly) without regard to gender, race, or age. Genetic links and tendencies have been found. However, I read a great article last year discussing the fallacy of genetically-linked diseases, which to summarize said that no common medical condition is likely to be the result of genetic traits unless it also confers some sort of evolutionary advantage (eg. sickle-cell anemia provides immunity to malaria). The researchers suggestion was to look to viruses, or even smaller structures like the prions that cause CJD (Human Mad Cow). So, I am left to wonder if these problems are not caused by the immune system being attacked by an as-yet undiscovered pathogen. My guess is that all three of these problems have a common cause. The genetic linkage is not so much that you have a genetic predisposition to a certain allergy, but that people who don't get it have a better natural (genetic) immunity to whatever the pathogen is, just like some people are better at not catching colds.
This is all very personal for me, because we have all three of these floating around in our family. It truly be a load off of all of us if someone could just figure this thing out. Any physicians reading this, please feel free to point out where I'm wrong.