The Killer Croc Differential

So today was the first day of dermatology lectures at my school.  I've never been that enthralled with the subject.  So I decided to do a little independent reading on dermatopathology and thought of (as usual) a comic book connection.  Perhaps one of the most famous comic book characters who has a skin condition is Waylon Jones aka Killer Croc. 

Okay, purported to have a skin condition.  But that's what I like about the Killer Croc character, his exact origin is still shrouded and unclear which fits with his status as an urban legend come to life.  Hopefully, it stays this way (I hated when Wolverine's origin was finally established - it was always more interesting when it was left to speculation).  In the couple decades he has been around, there have been numerous depictions of Killer Croc as well as explanations of his condition:

Killer Croc designed by Bruce Timm for Batman: The Animated Series

1. Atavism - a sort of evolutionary reversion.  In real life, this is seen as people with supernumary nipples, large canine teeth, or vestigial tails.  Depending on which depiction you follow, Croc is a mild to very dramatic example of atavism. 

Killer Croc as depicted by Lee Bermejo in Joker

2. Epidermolytic hyperkeratosis - a rare skin condition where the skin blisters and scales.  I am not quite sure where this first showed up in Croc stories but it was definitely featured in Batman: Gotham Knight, the animated tie-in to Christopher Nolan's Batman universe.  Again, Croc would be a pretty dramatic example but I like the possibility that Croc can be medically explained.

Killer Croc in Batman: Arkham Asylum
Designed by the folks at Wildstorm with obvious reference to
Jim Lee's design from Batman: Hush

3. Just a mutation - the comic book fall back explanation for anything real messed up.  Mutants are not featured as much in DC Comics as compared to the Marvel universe (Stan Lee always wanted semi-scientific explanations for his characters and stories) but Croc could just have mutated to be reptilian-like.