Infection starts off seeming trivial, yet escalates (4)

I believe the answer is:

stye

'infection' is the definition.
(stye is a kind of infection)

'starts off seeming trivial yet escalates' is the wordplay.
'starts off' suggests taking the first letters.
The initial letters of 'seeming trivial yet escalates' is 'STYE'.

(Other definitions for stye that I've seen before include "Ocular affliction" , "nasty spot" , "Eyelid problem" , "producing eyesore" , "Swelling near the eye" .)

I've seen this clue in The Independent.

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