Satoyoshi syndrome is a rare, multisystemic autoimmune disease mainly characterized by intermittent painful muscle spasms, alopecia (totalis or universalis in most cases) and long-lasting diarrhea that could lead to malnutrition, growth retardation, and amenorrhea. Secondary bone deformities and various endocrine anomalies may also be associated. Antinuclear antibodies are reported in many cases.

Altered immune function characterized by lymphoid proliferation, immune activation, and excessive autoreactivity often leading to autoimmune/inflammatory complications.