What are some diseases that are characterized by mysterious bruises?

Kidney disease, leukemia and Cushing's syndrome are fairly common conditions that are characterized by forming bruises easily, according to Healthline. Normal aging can also result in easy bruising, states Mayo Clinic.

Any condition that affects the ability to clot the blood, such as hemophilia or idiopathic thrombocytopenic purpura, can result in the appearance of bruises in response to even minor trauma, according to Healthline. Bruises occur when capillaries under the skin rupture and leak blood, states Mayo Clinic. Individuals who have defects in the ability to clot blood can leak enough blood from even a tiny rupture to form a visible bruise.