For other uses of "Purpura", see Purpura (disambiguation).
Classification and external resources
Petechiae and purpura on the low limb due to medication induced vasculitis
Purpura (from Latin: purpura, meaning "purple") is the appearance of red or purple discolorations on the skin that do not blanch on applying pressure. They are caused by bleeding underneath the skin usually secondary to vasculitis or dietary deficiency of vitamin C (scurvy). Purpura measure 0.3–1 cm (3–10 mm), whereas petechiae measure less than 3 mm, and ecchymoses greater than 1 cm.
This is common with typhus and can be present with meningitis caused by meningococcal meningitis or septicaemia. In particular, meningococcus (Neisseria meningitidis), a Gram-negative diplococcus organism, releases endotoxin when it lyses. Endotoxin activates the Hageman factor (clotting factor XII), which causes disseminated intravascular coagulation (DIC). The DIC is what appears as a rash on the affected individual.
Purpura are a common and nonspecific medical sign; however, the underlying mechanism commonly involves one of the following:
Platelet disorders (Thrombocytopenic purpura)
Primary thrombocytopenic purpura
Secondary thrombocytopenic purpura
Vascular disorders (nonthrombocytopenic purpura)
Microvascular injury, as seen in senile (old age) purpura, when blood vessels are more easily damaged
Deficient vascular support
Vasculitis, as in the case of Henoch-Schönlein purpura
Disseminated intravascular coagulation (DIC)
Scurvy (vitamin C deficiency) - defect in collagen synthesis due to lack of hydroxylation of procollagen results in weakened capillary walls and cells
Cocaine use with concomitant use of the one-time chemotherapy drug and now veterinary deworming agent levamisole can cause purpura of the ears, face, trunk, or extremities, sometimes needing reconstructive surgery. Levamisole is purportedly a common cutting agent
Decomposition of blood vessels including purpura are a symptom of acute radiation poisoning in excess of 2 Grays of radiation exposure. This is an uncommon cause in general but is commonly seen in victims of nuclear disaster.
There are also cases of psychogenic purpura described in the medical literature, some claimed to be due to "autoerythrocyte sensitization". Other studies suggest the local (cutaneous) activity of tPA can be increased in psychogenic purpura, leading to substantial amounts of localized plasmin activity, rapid degradation of fibrin clots, and resultant bleeding. Petechial rash is also characteristic of a rickettsial infection.
Bruise, which is a hematoma caused by trauma
Petechia, which is a small type of hematoma (<3mm)
Ecchymosis, which is a large type of hematoma (>1 cm)
^Mitchell RS; Kumar V; Robbins SL; Abbas AK; Fausto N (2007). Robbins basic pathology (8th ed.). Saunders/Elsevier. pp. 10–11. ISBN 1-4160-2973-7.
^"Toxic Effects of Levamisole in a Cocaine User". New England Journal of Medicine.
^Anderson JE, DeGoff W, McNamara M (1999). "Autoerythrocyte sensitization (psychogenic purpura): a case report and review of the literature". Pediatric emergency care15 (1): 47–8. doi:10.1097/00006565-199902000-00014. PMID 10069314.
^Lotti T, Benci M, Sarti MG, Teofoli P, Senesi C, Bonan P, et al. (1993). "Psychogenic purpura with abnormally increased tPA dependent cutaneous fibrinolytic activity". Int J Dermatol32 (7): 521–3. doi:10.1111/j.1365-4362.1993.tb02840.x. PMID 8340191.
Evaluating the Child with Purpura from American Academy of Family Physicians
Pathology: hematology, hematologic diseases of RBCs and megakaryocytes / MEP (D50-69,74, 280-287)
Micro-: Iron deficiency anemia
Macro-: Megaloblastic anemia
membrane: Hereditary spherocytosis
Southeast Asian ovalocytosis
Hemolytic disease of the newborn
Hereditary: Fanconi anemia
primary: Antithrombin III deficiency
Protein C deficiency/Activated protein C resistance/Protein S deficiency/Factor V Leiden
Sticky platelet syndrome
Thrombocytopenic purpura: ITP
platelet storage pool deficiency
Gray platelet syndrome
von Willebrand disease
cell/phys (coag, heme, immu, gran), csfs
rbmg/mogr/tumr/hist, sysi/epon, btst
drug (B1/2/3+5+6), btst, trns
Renal vein thrombosis
Ischaemic heart disease
large intestine: Ischemic colitis
small intestine: Mesenteric ischemia
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Considerations Purpura occurs when small blood vessels leak blood under the skin. When purpura spots are less than 3 millimeters in diameter, they are called petechiae. Purpura spots larger than 1 centimeter are ...