みみずばれ

み

ず

ば

れ

Meanings

welt; wale; weal

usually written using kana alone

A raised, red mark on the skin, often long and narrow like an earthworm, caused by a blow, insect bite, or allergic reaction.

腫はれ
腫れ is a general swelling, while みみずばれ specifically refers to a long, narrow raised mark like a welt.
青あおあざ
青あざ is a bruise (discoloration under the skin), whereas みみずばれ is a raised welt on the surface.

みみずばれUsage11%
Kana spelling is standard; usually written in kana.
みみず腫ばれUsage58%
Mixed kanji-hiragana spelling; less common than pure kana.
ミミズ腫ばれUsage32%
Mixed kanji-katakana spelling; ミミズ is often written in katakana for the earthworm, but the whole word is usually written in kana.
蚯蚓みみず腫ばれ
Full kanji spelling using rare characters; rarely used in practice.
蚯蚓みみず脹ばれ
rarely-used kanji form
Rare kanji form with 脹れ instead of 腫れ; it is rarely used.

Compound of みみず (earthworm) and 腫れ (swelling), from the resemblance of the raised mark to an earthworm.