The inexplicable appearance of bruising on the inner thighs indicates that there is bleeding under the skin on the inner thighs, that is, blood is leaking out of the blood vessels to the outside of the vessels, and this condition can be seen for a variety of reasons. One of the common diseases is called simple purpura, which is common in women of childbearing age, that is, bruising of the skin without any obvious trigger, along with routine blood tests, coagulation routine tests without any abnormalities, and good results with vitamin C treatment. In addition, vitamin C deficiency in the human body also causes inexplicable bruising on the inner thighs due to increased capillary permeability and decreased density. In addition, patients with thrombocytopenia may also develop inexplicable bruising on the inner thighs due to decreased hemostatic function of the body. For inexplicable bruising on the inner thighs, it is necessary to check the blood and coagulation routine to understand the specific cause of the bruising.