diff --git a/src/Symfony/Component/HttpFoundation/ParameterBag.php b/src/Symfony/Component/HttpFoundation/ParameterBag.php
index 84c0fb8055..43253de08f 100644
--- a/src/Symfony/Component/HttpFoundation/ParameterBag.php
+++ b/src/Symfony/Component/HttpFoundation/ParameterBag.php
@@ -229,7 +229,8 @@ class ParameterBag
      */
     public function getDigits($key, $default = '', $deep = false)
     {
-        return preg_replace('/[^[:digit:]]/', '', $this->get($key, $default, $deep));
+        // we need to remove - and + because they're allowed in the filter
+        return str_replace(array('-','+'),'', $this->filter($key, $default, $deep, FILTER_SANITIZE_NUMBER_INT));
     }
 
     /**