godan verb (-su), transitive verb
cause to swell; inflame
Transitive verb meaning to make a body part swell, often due to injury, allergy, or infection. Used with body parts like 顔, 目, 足, etc.
泣いて目を腫らした。
I cried and made my eyes swollen.
虫に刺されて足を腫らした。
I got bitten by a bug and my leg swelled up.
Standard kanji spelling for the transitive verb meaning 'to cause to swell'.
Kana spelling is common in everyday writing, especially when the kanji is not needed.
Intransitive counterpart meaning 'to swell' (something swells on its own). 腫らす is the transitive version meaning 'to cause to swell'.
Derived from the intransitive verb 腫れる (はれる, 'to swell') by changing the ending to the transitive す form. The kanji 腫 means 'swelling' or 'tumor'.