As you read in the title above; to update your Python packages via pip.

for Linux/*nix:

pip freeze --local | grep -v '^\-e' | cut -d = -f 1  | xargs -n1 pip install -U

p/s: you may need to run as sudo. Probably.

for Windows:

for /F "delims===" %i in ('pip freeze -l') do pip install -U %i

Credit:

http://stackoverflow.com/questions/2720014/upgrading-all-packages-with-pip