Abbas Di Palma, Shaykh Abbas Di Palma holds a BA and an MA degree in Islamic Studies, and certifications from the Language Institute of Damascus University. He has also studied traditional Islamic sciences in... Answered 1 year ago

as salam alaikum

the Qur'an says: "And whenever you are greeted with a greeting, greet with what is better than it or return the same" (4:86). 

Therefore in the above-mentioned case a full response should be given although it is preferable even a better response like "wa alaikum salam wa rahmatullah" or "wa alaikum salam wa rahmatullah wa barakatuhu".

With prayers for your success.