purpura
[per´pu-rah] a hemorrhagic disease characterized by extravasation of blood into the tissues, under the skin, and through the mucous membranes, and producing spontaneous bruises, ecchymoses, and petechiae (small hemorrhagic spots) on the skin. (See plate in Dermatology Atlas.) When accompanied by a decrease in the circulating platelets, it is called
thrombocytopenic purpura; when there is no decrease in the platelet count, it is called
nonthrombocytopenic purpura. adj.,
adj purpu´ric.
There are two general types of thrombocytopenic purpura:
primary or
idiopathic, in which the cause is unknown, and
secondary or
symptomatic, which may be associated with exposure to drugs or other chemical agents, systemic diseases such as multiple myeloma and leukemia, diseases affecting the bone marrow or spleen, and infectious diseases such as rubella (German measles).
Symptoms. The outward manifestations and laboratory findings of primary and secondary thrombocytopenic purpura are similar. There is evidence of bleeding under the skin, with easy bruising and the development of petechiae. In the acute form there may be bleeding from any of the body orifices, such as hematuria, nosebleed, vaginal bleeding, and bleeding gums. The
platelet count is below 100,000 per cubic millimeter of blood and may go as low as 10,000 per cubic millimeter (normal count is about 250,000 per cubic millimeter). The bleeding time is prolonged and clot retraction is poor. Coagulation time is normal.
Treatment. Differential diagnosis is necessary to determine the type of purpura present and to eliminate the cause if it can be determined. General measures include protection of the patient from trauma, elective surgery, and tooth extractions, any one of which may lead to severe or even fatal hemorrhage. In the thrombocytopenic form, corticosteroids may be administered when the purpura is moderately severe and of short duration. Splenectomy is indicated when other, more conservative measures fail and is successful in a majority of cases. In some instances, especially in children, there may be spontaneous and permanent recovery from idiopathic purpura. (See Atlas 2, Part Q.)
annular telangiectatic purpura a rare form in which pinpoint reddened lesions coalesce to form a ring-shaped or continuously linked pattern, commonly beginning in the lower extremities and becoming generalized. Called also
Majocchi's disease.
fibrinolytic purpura purpura associated with increased fibrinolytic activity of the blood.
purpura ful´minans a form of nonthrombocytopenic purpura seen mainly in children, usually after an infectious disease, marked by fever, shock, anemia, and sudden, rapidly spreading symmetrical skin hemorrhages of the lower limbs, often associated with extensive intravascular thromboses and gangrene.
idiopathic thrombocytopenic purpura thrombocytopenic purpura not directly associated with any definable systemic disease, although it often follows a systemic infection; the cause is thought to be an IgG immunoglobulin that acts as an antibody against platelets, causing ecchymoses, petechiae, and other bleeding. There are both acute and chronic forms: the
acute form has a sudden onset, is more common in children, and usually resolves spontaneously within a few months; the
chronic form has a slower onset, is more common in adults, and may be recurrent.
nonthrombocytopenic purpura purpura without any decrease in the platelet count of the blood. In such cases the cause is either abnormal capillary fragility or a clotting factor deficiency.
purpura seni´lis dark purplish red ecchymoses occurring on the forearms and backs of the hands in the elderly.
thrombocytopenic purpura purpura associated with a decrease in the number of platelets in the blood; see
purpura. Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.