Initially sitting on child’s toilet suffering from rash? (6)
I believe the answer is:
spotty
'suffering from rash?' is the definition.
'initially sitting on child's toilet' is the wordplay.
'initially' suggests taking the first letters.
'on' means one lot of letters go next to another.
'child's toilet' becomes 'potty'.
The first letter of 'sitting' is 's'.
's'+'potty'='SPOTTY'
(Other definitions for spotty that I've seen before include "Suffering as a teenager" , "Maculate (like a leopard?)" , "irregular" , "Freckled" , "Suffering from acne" .)