The term purpura refers to a group of bleeding disorders characterized by purplish or brownish-red discolorations, easily visible through the skin's outer layer, that are caused by hemorrhaging (internal bleeding) into the tissues.

Common Purpura

Common purpura (also called simple purpura or senile purpura) is the most widespread of the disorders and is marked by easy skin bruising and increased blood vessel fragility. Common purpura is an inherited condition that occurs most commonly in postmenopausal women. The condition often affects thigh tissue and produces large bruises rather than hemorrhages. The bleeding may be intensified by surgery or injury.

Henoch-Schonlein Purpura

Henoch-Schonlein purpura (also known as allergic purpura and anaphylactoid purpura) most often affects children. Henoch-Schonlein purpura may be associated with some forms of arthritis, gastrointestinal disorders, kidney failure, and erythema (redness of the skin).

Purpura Fulminans

Purpura fulminans is most often seen in children, occurring mainly after an infectious disease. The condition is marked by fever, shock, anemia, rapidly spreading symmetrical skin hemorrhages in the lower limbs, intravascular thrombosis (blockage of a blood vessel by a solid mass), and gangrene.

Idiopathic Thrombocytopenic Purpura

Thrombocytopenic purpura is a disorder in which the number of platelets (the tiny elements in the blood that are vital to clotting) is decreased, whether because of a primary disease or as a consequence of another blood disorder. It can be an early manifestation of HIV infection.

Causes

Causes vary with the type of purpura. Common purpura in postmenopausal women appears to result from decreased estrogen (female hormone) levels and thinning of the deep layers of the skin. Henoch-Schönlein purpura may result from sensitivities developed after an infection or allergic reaction. Purpura in the elderly is often due to the fragility of their skin.

There are also temporary forms of purpura in which vascular bleeding occurs as a result of fever, hypothyroidism (low output of thyroid hormone), generalized illness, defects in the small blood vessels, or a drug reaction to certain medications, such as aspirin. Purpura can sometimes stem from wearing overly tight clothing or from sustaining an injury, such as a black eye.

Diagnosis

Laboratory testing is essential in all cases of possible purpura in order to exclude other causes. Perhaps the most difficult of the forms of purpura to diagnose is Henoch-Schönlein purpura. Joint pain and bouts of abdominal pain in this disorder may mimic acute abdominal conditions or forms of arthritis. Later, kidney involvement during the course of this form of purpura may cause a misdiagnosis of kidney disease.

Treatment

In the case of Henoch-Schonlein purpura, it is advisable to eliminate the possible allergic cause. Corticosteroid medications (artificial hormones) are often prescribed. Immunosuppressive therapy (suppression of the immune system by means of drugs) is sometimes useful in treating the various forms of purpura.

If the purpura is thrombocytopenic, the spleen (an abdominal organ that is a component of the circulatory system) may be removed if it is hoarding too many platelets. Milder cases of the condition often improve with treatment or spontaneously.

Prevention

Estrogen therapy has proved helpful in preventing or relieving common purpura in postmenopausal women. Other than preventive measures to avoid infections or allergic reactions, there is little that can be done to prevent purpura.