diff --git a/pandas/core/arrays/integer.py b/pandas/core/arrays/integer.py
index e9d51aaea4218..87dc5f8aaf1e4 100644
--- a/pandas/core/arrays/integer.py
+++ b/pandas/core/arrays/integer.py
@@ -58,6 +58,11 @@ def numpy_dtype(self):
     def kind(self):
         return self.numpy_dtype.kind
 
+    @cache_readonly
+    def itemsize(self):
+        """ Return the number of bytes in this dtype """
+        return self.numpy_dtype.itemsize
+
     @classmethod
     def construct_array_type(cls):
         """Return the array type associated with this dtype
diff --git a/pandas/tests/extension/test_integer.py b/pandas/tests/extension/test_integer.py
index efee647389884..218b2e9bd0e11 100644
--- a/pandas/tests/extension/test_integer.py
+++ b/pandas/tests/extension/test_integer.py
@@ -174,6 +174,10 @@ class TestGetitem(base.BaseGetitemTests):
     pass
 
 
+class TestSetitem(base.BaseSetitemTests):
+    pass
+
+
 class TestMissing(base.BaseMissingTests):
     pass