Och no. There's no great significance to the thistle. I just wanted the blog to look more interesting than the basic template. I wanted some image that conveyed eczema in the abstract. The real thing isn't very attractive--if you have it, you know what I'm talking about. So I considered some photos of scratched glass, metal, etc-- distressed material. All too grim or industrial. The idea was not to be negative.
The thistle-- it's kind of pretty, no? But prickly as hell, and can scratch you up. "Prickly" also nails how I feel when I've got a flare-up. I'm irritable, anti-social, and snap at my loved ones. Maybe I'd be a curmudgeon without the eczema-- the point is moot, since it's a part of me and always will be.