diff --git a/modules/lang/elixir/config.el b/modules/lang/elixir/config.el
index 688bb591c..8b5cee237 100644
--- a/modules/lang/elixir/config.el
+++ b/modules/lang/elixir/config.el
@@ -5,12 +5,8 @@
 
 (after! highlight-numbers
   (puthash 'elixir-mode
-    (rx (and symbol-start
-            (? "-")
-            (+ digit)
-            (0+ (and "_" (= 3 digit)))
-            symbol-end))
-    highlight-numbers-modelist))
+           "\\_<-?[[:digit:]]+\\(?:_[[:digit:]]\\{3\\}\\)*\\_>"
+           highlight-numbers-modelist))
 
 ;;
 ;;; Packages