diff --git a/docs/highlighters/pattern.md b/docs/highlighters/pattern.md
index 3ad5f24..8853db0 100644
--- a/docs/highlighters/pattern.md
+++ b/docs/highlighters/pattern.md
@@ -9,6 +9,9 @@ This is the `pattern` highlighter, that highlights user-defined patterns.
 To use this highlighter, associate patterns with styles in the
 `ZSH_HIGHLIGHT_PATTERNS` associative array, for example in `~/.zshrc`:
 
+    # Declare the variable
+    typeset -A ZSH_HIGHLIGHT_PATTERNS
+
     # To have commands starting with `rm -rf` in red:
     ZSH_HIGHLIGHT_PATTERNS+=('rm -rf *' 'fg=white,bold,bg=red')