@JaneAir - I know a few people that have a few of these conditions too. It seems like allergies, asthma, and eczema all go together. As you said, filaggrin gene mutations could explain why.
I also think it's interesting that this gene mutation might be the cause of nickle allergies as well. Or rather, to allergic reactions to nickle. I can see why having more nickle passing through your skin would cause more of a reaction. I bet some people have mild nickle allergies, but don't know about it because their filaggrin proteins work normally!