Perhaps:
from os.path import dirname
def parents(p):
while len(p) > 1:
p = dirname(p)
yield p
pathsManaged = ['/a/b', '/c/d', '/e']
currPath = '/e/a'
if any(p in pathsManaged for p in parents(currPath)):
print 'subdir of already managed path'
prints:
subdir of already managed path