Wool covers an eczema trigger?

[mum2sarah]

I was discussing with a friend my preference for natural cloth diaper fibers, and mentioned that I planned to use wool covers with DS-on-the-way.  She warned me that wool can be an eczema trigger, since we'd been talking earlier about how my DD#2 has nummular eczema problems.  What I can find online seems to suggest wool can indeed be an eczema trigger but everything I've read seems to talk about it in the sense of a current/active trigger, but DD#2 never had eczema as an infant.  My question is, could exposure to wool as an infant act as an eczema trigger later in life?  I did use wool covers with DD#2 but I didn't always use a cover at all and we also did EC so she was fully potty-trained by 8 months of age; thus, I'd say her exposure to wool was minimal.  And she didn't start developing nummular eczema til the age of 4.  But with DD#1 I didn't use wool at all and she has no eczema issues, nor have we been able to identify any allergies or alternative explanations for why DD#2 suffers from eczema issues.  Is this just coincidence?  Should I suddenly be wary of wool for DS-on-the-way?