diff --git a/resources/trackers/kitsu.py b/resources/trackers/kitsu.py
index 581bb2c..48b5287 100644
--- a/resources/trackers/kitsu.py
+++ b/resources/trackers/kitsu.py
@@ -415,27 +415,28 @@ class Kitsu(Tracker):
     def update_data(self, entity, custom_data={}, name=None, description=None, frames=None, clear=False):
         if isinstance(entity, dict):
             entity_id = entity['id']
+            existing_data = entity.get('data') or {}
         else:
             entity_id = self.get_id(entity)
-            entity = gazu.client.fetch_one('entities', entity_id)
+            existing_data = None
 
+        payload = {}
         if name:
-            entity['name'] = name
+            payload['name'] = name
         if description:
-            entity['description'] = description
+            payload['description'] = description
         if frames:
-            entity['nb_frames'] = frames
+            payload['nb_frames'] = frames
 
-        if clear or not entity['data']:
-            entity['data'] = custom_data
-        else:
-            entity['data'].update(custom_data)
+        if custom_data or clear:
+            if clear:
+                payload['data'] = dict(custom_data)
+            else:
+                if existing_data is None:
+                    existing_data = gazu.client.fetch_one('entities', entity_id).get('data') or {}
+                payload['data'] = {**existing_data, **custom_data}
 
-        #print('######UPDATE DATA')
-        #pprint(entity)
-        entity_data = gazu.client.put(f"data/entities/{entity_id}", entity)
-        #print()
-        #pprint(entity)
+        entity_data = gazu.client.put(f"data/entities/{entity_id}", payload)
 
         return entity_data['data']