That’s an interesting question, and I don’t know. The only alternatives for English I found were somewhat obvious combos like “smell blindness”. If I had to guess, probably it just isn’t common or disabling enough to come up often, so it doesn’t get its own word.

Think it is the word for the symptom rather than the diagnosis, much like deaf or blind are, just that English doesn't have a casual term for it.

The lack of a casual term may be because though the sense of smell is very useful & has a safety/survival component, being anosmic is unlikely to leave a person requiring much by way of additional skills and/or tools relative to deafness or blindness.