I have a cut on a knuckle which occasionally opens (usually during winter), to disappear after some time (it is usually fine during the summer). This is going on for years now and yes, I will show this to my doctor (it is more a nuisance than anything else but there is the risk of infection).
Then during a recent discussion about the Vietnam War, the story of Phan Thi Kim Phuc was mentioned and I recall that I read years ago that she said (quoting from memory) that "[her] wounds still open, usually in summer".
I was wondering what is the mechanism of such wounds which heal, but not completely (to reopen after some time or on some conditions).
Her story is horrific and the extent of her wounds (and also the nature of the wound - inflicted by Napalm) make me think that there may have been some changes in the skin so deep that the consistency of the skin is not there anymore (wildly speculating).
In my absolutely minor case, however, there are no particular reasons for the wound to open - it is just closed and then, sometimes, decides to reopen to re-heal some time afterwards. Since this is otherwise healthy skin (it looks perfect when the cut is closed) I wonder if there are mechanical or chemical reasons for these behaviours?