diff --git a/src/main/java/de/caritas/cob/userservice/api/adapters/web/dto/UserDTO.java b/src/main/java/de/caritas/cob/userservice/api/adapters/web/dto/UserDTO.java
index b7cbcea95..aade164b9 100644
--- a/src/main/java/de/caritas/cob/userservice/api/adapters/web/dto/UserDTO.java
+++ b/src/main/java/de/caritas/cob/userservice/api/adapters/web/dto/UserDTO.java
@@ -12,6 +12,7 @@
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
+import com.google.common.collect.Lists;
 import de.caritas.cob.userservice.api.adapters.web.dto.serialization.EncodeUsernameJsonDeserializer;
 import de.caritas.cob.userservice.api.adapters.web.dto.serialization.UrlDecodePasswordJsonDeserializer;
 import de.caritas.cob.userservice.api.adapters.web.dto.validation.ValidAge;
@@ -117,7 +118,7 @@ public class UserDTO implements UserRegistrationDTO {
 
   @ApiModelProperty(required = false, example = "\"[1,5]\"")
   @JsonProperty("topicIds")
-  private Collection<Integer> topicIds;
+  private Collection<Integer> topicIds = Lists.newArrayList();
 
   @ApiModelProperty(required = false, example = "\"RELATIVE_COUNSELLING\"")
   @JsonProperty("counsellingRelation")
diff --git a/src/main/java/de/caritas/cob/userservice/api/service/consultingtype/TopicService.java b/src/main/java/de/caritas/cob/userservice/api/service/consultingtype/TopicService.java
index 6d2c6cb2c..f6e348517 100644
--- a/src/main/java/de/caritas/cob/userservice/api/service/consultingtype/TopicService.java
+++ b/src/main/java/de/caritas/cob/userservice/api/service/consultingtype/TopicService.java
@@ -1,5 +1,6 @@
 package de.caritas.cob.userservice.api.service.consultingtype;
 
+import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
 import de.caritas.cob.userservice.api.config.CacheManagerConfig;
 import de.caritas.cob.userservice.api.config.apiclient.TopicServiceApiControllerFactory;
@@ -67,7 +68,13 @@ private Map<Long, TopicDTO> getAllTopicsMap(List<TopicDTO> allTopics) {
   }
 
   public List<String> findTopicsInternalAttributes(Collection<Integer> topicsList) {
-    return topicsList.stream().map(this::findTopicInternalIdentifier).collect(Collectors.toList());
+    if (topicsList == null) {
+      return Lists.newArrayList();
+    } else {
+      return topicsList.stream()
+          .map(this::findTopicInternalIdentifier)
+          .collect(Collectors.toList());
+    }
   }
 
   public String findTopicInternalIdentifier(Integer topicId) {