diff --git a/Dockerfile.phptest b/Dockerfile.phptest
index a8e6004..f153b71 100644
--- a/Dockerfile.phptest
+++ b/Dockerfile.phptest
@@ -3,8 +3,7 @@
 
 FROM registry.dege.au/leenooks/php:8.1-fpm-alpine
 
-# Enable xdebug
-RUN pecl_install xdebug
-
 # Add other built tools
-RUN apk add npm
+RUN apk --no-cache add npm linux-headers \
+ && pecl_install xdebug \
+ && apk --no-cache del linux-headers