Purple bruising on arms is likely purpura, which can arise due to many conditions, including thrombocytopenia, according to Healthline. Purpura can also be caused by conditions such as scurvy, inflammation in the blood vessels, an infection in the bloodstream, recent blood transfusions and certain medications.
Thrombocytopenia refers to any condition that causes an abnormally low amount of platelets in the blood, explains MedlinePlus. There are usually three causes of low blood platelets, including not enough platelets created in the bone marrow, and increased platelet breakdown in the bloodstream or spleen. Conditions that lead to an inadequate platelet count include leukemia, a folate deficiency, bone marrow infections and myelodysplastic syndrome. Not all patients with thrombocytopenia have symptoms, which can include bleeding in the mouth, bruising, nosebleeds and a rash.
Scurvy is a disease that affects the skin and blood vessels and occurs when the body is deficient in vitamin C, according to Healthgrades. Risk factors for developing the condition include smoking, not taking medications, eating an unhealthy diet and consuming alcohol. Some conditions that cause malnutrition can also aggravate scurvy, which can result in gum disease, skin hemorrhaging, recurrent infections and anemia. Some patients do not have constant symptoms of scurvy or have mild ones, such as fatigue.