Inflammation of the ear? It is to be treated (6)
I believe the answer is:
otitis
'inflammation of the ear?' is the definition.
(I've seen this in another clue)
'it is to be treated' is the wordplay.
'be treated' is an anagram indicator.
'it'+'is'+'to'='itisto'
'itisto' anagrammed gives 'OTITIS'.
(Other definitions for otitis that I've seen before include "trouble with hearing device" , "pain" , "Inflammation of the ear" , "problem for listener" , "Condition of shell-like" .)