Sodium hydroxide (NaOH) is lye, which shouldn't be consumed. Pretzel salt is sodium chloride (NaCL).
"Lauge" is German for "lye". They're called that because they're made with it.
[1]: Though when I switched my phone keyboard to German just now to test it out, the predictive spelling corrector suggested "Laugenbrezel", not "-brötchen", when I'd got as far as "Laugenb".