diff --git a/src/Middleware/SCIMHeaders.php b/src/Middleware/SCIMHeaders.php
index a392dd8..fcd9122 100644
--- a/src/Middleware/SCIMHeaders.php
+++ b/src/Middleware/SCIMHeaders.php
@@ -10,7 +10,9 @@ class SCIMHeaders
 {
     public function handle(Request $request, Closure $next)
     {
-        if ($request->method() != 'GET' && stripos($request->header('content-type'), 'application/scim+json') === false && stripos($request->header('content-type'), 'application/json') === false && strlen($request->getContent()) > 0) {
+        $contentType = $request->header('content-type', '');
+
+        if ($request->method() != 'GET' && stripos($contentType, 'application/scim+json') === false && stripos($contentType, 'application/json') === false && strlen($request->getContent()) > 0) {
             throw new SCIMException(sprintf('The content-type header should be set to "%s"', 'application/scim+json'));
         }