There are many small bruises on the thighs, which may be caused by local trauma. It is possible that the blood vessels below the local skin are not functioning too healthy and are too brittle. Such mild trauma can lead to subcutaneous bruising and bruising, or it may be cutaneous vasculitis of the thigh. Because cutaneous vasculitis is atopic, it may cause some non-specific inflammatory changes in the local skin. These inflammations can lead to the involvement of the blood vessels below the skin, causing a certain inflammatory response that manifests as bruising manifestations.