You already loop through every key of %hash1, so you don't need to check in the hash again

%hash1 = ("TEXT", 25);
%hash2 = ("text", 25);
foreach $item1 (keys(%hash1)) {
  foreach $item2 (keys(%hash2)) {
    if (lc $item1 eq lc $item2}) { print "matches\n";}
  }
}
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By the way, as long as your hashes are small (say <200 entries) or time is not important, your algorithm is fine, but if not, then you might generate a second hash with the lowercase keys of one of the hashes and then check the second hash against that:

%hash1 = ("TEXT", 25);
%hash2 = ("text", 25);
foreach $item1 (keys(%hash1)) {
  $lchash1{lc $item1}=1;
}
foreach $item2 (keys(%hash2)) {
    if (exists $lchash1{lc $item2}) { print "matches\n";}
  }
}
[download]