diff --git a/encoding/protojson/encode.go b/encoding/protojson/encode.go
index 29846df..0e72d85 100644
--- a/encoding/protojson/encode.go
+++ b/encoding/protojson/encode.go
@@ -216,9 +216,7 @@
 		}
 
 		v := m.Get(fd)
-		isProto2Scalar := fd.Syntax() == protoreflect.Proto2 && fd.Default().IsValid()
-		isSingularMessage := fd.Cardinality() != protoreflect.Repeated && fd.Message() != nil
-		if isProto2Scalar || isSingularMessage {
+		if fd.HasPresence() {
 			if m.skipNull {
 				continue
 			}