children's diseases
疳 centers on childhood ailments, especially chronic digestive or nutritional disorders. The meaning is narrow and refers specifically to children's diseases.
疳 combines the sickness radical 疒 with 甘, which likely contributes the sound カン. The character was created to name a specific category of childhood illness.
The sickness enclosure 疒 wraps around 甘 (sweet). Picture a child with a chronic illness who can only stomach sweet, bland foods.
For カン, imagine a can of sweet medicine given to a sick child: can -> カン, and the sweet taste 甘 inside the sickness 疒 helps the child recover.
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