Babies may shiver due to mild or early calcium deficiency, which can lead to neurological and psychiatric symptoms. Severe deficiency may be accompanied by abnormalities in the skeletal and muscular systems.

The reasons for nail loss after recovery from hand, foot, and mouth disease may include nutritional deficiencies such as iron deficiency anemia, calcium deficiency, and vitamin deficiencies. Treatment methods include enhancing nutrition and administering gamma globulin injections to boost immunity.