疳かんの虫むし

noun

convulsions in a child; nervousness; short-temperedness

Traditional expression for a child's irritability, fretfulness, or convulsions, often attributed to an imaginary 'bug' in old folk belief. In modern usage, it refers to a child's bad mood or tantrums.

• 赤あかちゃんが泣なき止やまないのは、疳かんの虫むしが強つよいからかもしれない。

  The baby won't stop crying; maybe it's because the 'kan no mushi' is strong.

• うちの子こは疳かんの虫むしがひどくて、よくかんしゃくを起おこす。

  My child has a bad case of 'kan no mushi' and often throws tantrums.

noun

bug thought to cause children's diseases

Historical folk belief: an imaginary insect or worm in a child's stomach thought to cause convulsions and irritability. Now only used when explaining the origin of the expression.

• 昔むかしは、子こどもの癇かん癪しゃくは疳かんの虫むしという虫むしのせいだと信しんじられていた。

  In the past, it was believed that a child's tantrums were caused by a bug called 'kan no mushi'.