Error when proxying to blog sub domain from node.js application - node.js

Question

I have a nodejs app hosted on heroku, on www.example.com
I then have a wordpress blog, currently on a subdomain - blog.example.com
I have a route setup in express:
(using express-http-proxy)
var proxy = require('express-http-proxy');
app.use('/blog', proxy('blog.example.com', {
forwardPath: function(req, res) {
return require('url').parse(req.url).path;
}
}));
This works, in the sense that I can see the blog "home page" on www.example.com/blog - it's proxying correctly and transparnelty to blog.example.com
However, if I visit any of the blog posts on there, it falls over with a 500 error
[error] [client (ipAddressHere)] Request exceeded the limit of 10 internal redirects due to probable configuration error. Use 'LimitInternalRecursion' to increase the limit if necessary. Use 'LogLevel debug' to get a backtrace., referer: http://www.example.com/blog/
I suspect it’s something to do with my htaccess - but can’t quite figure out what?
My htaccess is:
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /blog/
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /blog/index.php [L]
</IfModule>
# END WordPress

Answer 1

Removed /blog from my htaccess to make it:
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress
It now works
Transparent proxying from my node app /blog to wordpress blog!