Complaint from this writer as beer's missing head (7)
I believe the answer is:
measles
'complaint' is the definition.
(measles is a kind of disease)
'this writer as beer's missing head' is the wordplay.
'this writer' becomes 'me' (the person who is writing these clues).
'beer's' becomes 'ales'.
'missing head' means to remove the first letter.
'ales' with its initial letter taken away is 'les'.
'me'+'as'+'les'='MEASLES'
'from' is the link.
(Other definitions for measles that I've seen before include "Infection marked by red spots" , "Viral disease with rash" , "Disease where spots may be seen" , "Viral disease once common in children" , "Children's disease with red spots" .)