diff --git a/datadog_lambda/metric.py b/datadog_lambda/metric.py
index 6b13eb3b..ac235198 100644
--- a/datadog_lambda/metric.py
+++ b/datadog_lambda/metric.py
@@ -108,19 +108,20 @@ def submit_errors_metric(lambda_context):
 
 
 # Set API Key and Host in the module, so they only set once per container
-DD_API_KEY_SECRET_ARN = os.environ.get("DD_API_KEY_SECRET_ARN", "")
-DD_KMS_API_KEY = os.environ.get("DD_KMS_API_KEY", "")
-DD_API_KEY = os.environ.get("DD_API_KEY", os.environ.get("DATADOG_API_KEY", ""))
-if DD_API_KEY_SECRET_ARN:
-    api._api_key = boto3.client("secretsmanager").get_secret_value(
-        SecretId=DD_API_KEY_SECRET_ARN
-    )["SecretString"]
-elif DD_KMS_API_KEY:
-    api._api_key = boto3.client("kms").decrypt(
-        CiphertextBlob=base64.b64decode(DD_KMS_API_KEY)
-    )["Plaintext"]
-else:
-    api._api_key = DD_API_KEY
+if not api._api_key:
+    DD_API_KEY_SECRET_ARN = os.environ.get("DD_API_KEY_SECRET_ARN", "")
+    DD_KMS_API_KEY = os.environ.get("DD_KMS_API_KEY", "")
+    DD_API_KEY = os.environ.get("DD_API_KEY", os.environ.get("DATADOG_API_KEY", ""))
+    if DD_API_KEY_SECRET_ARN:
+        api._api_key = boto3.client("secretsmanager").get_secret_value(
+            SecretId=DD_API_KEY_SECRET_ARN
+        )["SecretString"]
+    elif DD_KMS_API_KEY:
+        api._api_key = boto3.client("kms").decrypt(
+            CiphertextBlob=base64.b64decode(DD_KMS_API_KEY)
+        )["Plaintext"]
+    else:
+        api._api_key = DD_API_KEY
 logger.debug("Setting DATADOG_API_KEY of length %d", len(api._api_key))
 
 # Set DATADOG_HOST, to send data to a non-default Datadog datacenter