Doctor met diarist to make superficial complaint (10)
I believe the answer is:
dermatitis
'superficial complaint' is the definition.
(medical complaint on the skin)
'doctor met diarist' is the wordplay.
'doctor' indicates anagramming the letters.
'met'+'diarist'='metdiarist'
'metdiarist' anagrammed gives 'DERMATITIS'.
'to make' is the link.
(Other definitions for dermatitis that I've seen before include "Skin inflammation" , "Skin trouble" , "Skin ailment" , "Met diarist (anag.)" .)