diff --git a/dd-java-agent/instrumentation/apache-httpasyncclient-4/src/main/java/datadog/trace/instrumentation/apachehttpasyncclient/ApacheHttpAsyncClientDecorator.java b/dd-java-agent/instrumentation/apache-httpasyncclient-4/src/main/java/datadog/trace/instrumentation/apachehttpasyncclient/ApacheHttpAsyncClientDecorator.java
index e8faa71340d..d9fd30b6a42 100644
--- a/dd-java-agent/instrumentation/apache-httpasyncclient-4/src/main/java/datadog/trace/instrumentation/apachehttpasyncclient/ApacheHttpAsyncClientDecorator.java
+++ b/dd-java-agent/instrumentation/apache-httpasyncclient-4/src/main/java/datadog/trace/instrumentation/apachehttpasyncclient/ApacheHttpAsyncClientDecorator.java
@@ -60,9 +60,16 @@ protected int status(final HttpContext context) {
 
   @Override
   protected String getRequestHeader(HttpUriRequest request, String headerName) {
-    Header header = request.getFirstHeader(headerName);
-    if (header != null) {
-      return header.getValue();
+    Header[] headers = request.getHeaders(headerName);
+    if (headers.length > 0) {
+      StringBuilder result = new StringBuilder();
+      for (int i = 0; i < headers.length; i++) {
+        result.append(headers[i].getValue());
+        if (i + 1 < headers.length) {
+          result.append(",");
+        }
+      }
+      return result.toString();
     }
     return null;
   }
@@ -71,9 +78,16 @@ protected String getRequestHeader(HttpUriRequest request, String headerName) {
   protected String getResponseHeader(HttpContext context, String headerName) {
     final Object responseObject = context.getAttribute(HttpCoreContext.HTTP_RESPONSE);
     if (responseObject instanceof HttpResponse) {
-      Header header = ((HttpResponse) responseObject).getFirstHeader(headerName);
-      if (header != null) {
-        return header.getValue();
+      Header[] headers = ((HttpResponse) responseObject).getHeaders(headerName);
+      if (headers.length > 0) {
+        StringBuilder result = new StringBuilder();
+        for (int i = 0; i < headers.length; i++) {
+          result.append(headers[i].getValue());
+          if (i + 1 < headers.length) {
+            result.append(",");
+          }
+        }
+        return result.toString();
       }
     }
     return null;
diff --git a/dd-java-agent/instrumentation/apache-httpclient-4/src/main/java/datadog/trace/instrumentation/apachehttpclient/ApacheHttpClientDecorator.java b/dd-java-agent/instrumentation/apache-httpclient-4/src/main/java/datadog/trace/instrumentation/apachehttpclient/ApacheHttpClientDecorator.java
index 91cee1f3f85..20bfcdfcddd 100644
--- a/dd-java-agent/instrumentation/apache-httpclient-4/src/main/java/datadog/trace/instrumentation/apachehttpclient/ApacheHttpClientDecorator.java
+++ b/dd-java-agent/instrumentation/apache-httpclient-4/src/main/java/datadog/trace/instrumentation/apachehttpclient/ApacheHttpClientDecorator.java
@@ -46,18 +46,32 @@ protected int status(final HttpResponse httpResponse) {
 
   @Override
   protected String getRequestHeader(HttpUriRequest request, String headerName) {
-    Header header = request.getFirstHeader(headerName);
-    if (null != header) {
-      return header.getValue();
+    Header[] headers = request.getHeaders(headerName);
+    if (headers.length > 0) {
+      StringBuilder result = new StringBuilder();
+      for (int i = 0; i < headers.length; i++) {
+        result.append(headers[i].getValue());
+        if (i + 1 < headers.length) {
+          result.append(",");
+        }
+      }
+      return result.toString();
     }
     return null;
   }
 
   @Override
   protected String getResponseHeader(HttpResponse response, String headerName) {
-    Header header = response.getFirstHeader(headerName);
-    if (null != header) {
-      return header.getValue();
+    Header[] headers = response.getHeaders(headerName);
+    if (headers.length > 0) {
+      StringBuilder result = new StringBuilder();
+      for (int i = 0; i < headers.length; i++) {
+        result.append(headers[i].getValue());
+        if (i + 1 < headers.length) {
+          result.append(",");
+        }
+      }
+      return result.toString();
     }
     return null;
   }
diff --git a/dd-java-agent/instrumentation/apache-httpclient-5/src/main/java/datadog/trace/instrumentation/apachehttpclient5/ApacheHttpClientDecorator.java b/dd-java-agent/instrumentation/apache-httpclient-5/src/main/java/datadog/trace/instrumentation/apachehttpclient5/ApacheHttpClientDecorator.java
index 78d7958d6f6..1fd29d79528 100644
--- a/dd-java-agent/instrumentation/apache-httpclient-5/src/main/java/datadog/trace/instrumentation/apachehttpclient5/ApacheHttpClientDecorator.java
+++ b/dd-java-agent/instrumentation/apache-httpclient-5/src/main/java/datadog/trace/instrumentation/apachehttpclient5/ApacheHttpClientDecorator.java
@@ -54,18 +54,32 @@ protected int status(final HttpResponse httpResponse) {
 
   @Override
   protected String getRequestHeader(HttpRequest request, String headerName) {
-    Header header = request.getFirstHeader(headerName);
-    if (null != header) {
-      return header.getValue();
+    Header[] headers = request.getHeaders(headerName);
+    if (headers.length > 0) {
+      StringBuilder result = new StringBuilder();
+      for (int i = 0; i < headers.length; i++) {
+        result.append(headers[i].getValue());
+        if (i + 1 < headers.length) {
+          result.append(",");
+        }
+      }
+      return result.toString();
     }
     return null;
   }
 
   @Override
   protected String getResponseHeader(HttpResponse response, String headerName) {
-    Header header = response.getFirstHeader(headerName);
-    if (null != header) {
-      return header.getValue();
+    Header[] headers = response.getHeaders(headerName);
+    if (headers.length > 0) {
+      StringBuilder result = new StringBuilder();
+      for (int i = 0; i < headers.length; i++) {
+        result.append(headers[i].getValue());
+        if (i + 1 < headers.length) {
+          result.append(",");
+        }
+      }
+      return result.toString();
     }
     return null;
   }