diff --git a/lib/ninetails/key_conversion.rb b/lib/ninetails/key_conversion.rb
index <HASH>..<HASH> 100644
--- a/lib/ninetails/key_conversion.rb
+++ b/lib/ninetails/key_conversion.rb
@@ -15,8 +15,14 @@ module Ninetails
       end
     end
 
+    def should_modify_keys?
+      @headers["Content-Type"].present? &&
+        @headers["Content-Type"].include?("application/json") &&
+        Ninetails::Config.key_style == :camelcase
+    end
+
     def modify_keys(body)
-      if @headers["Content-Type"].include?("application/json") && Ninetails::Config.key_style == :camelcase
+      if should_modify_keys?
         body = JSON.parse(body).convert_keys -> (key) { key.camelcase :lower }
         body.to_json
       else
Check if Content-Type is present before running key conversion