Purpura
Encyclopedia
Purpura 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. Purpura measure 0.3–1 cm (3–10 mm), whereas petechia
e 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, a Gram-negative
diplococci organism, releases endotoxin when it lyses. Endotoxin activates the Hageman factor (clotting factor XII), which causes disseminated intravascular coagulation. The DIC
is what appears as a rash on the affected individual.
There are also cases of psychogenic purpura described in the medical literature, some claimed to be due to "autoerythrocyte sensitization." Other studies suggest, that 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.
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
that do not blanch on applying pressure. They are caused by bleeding
Bleeding
Bleeding, technically known as hemorrhaging or haemorrhaging is the loss of blood or blood escape from the circulatory system...
underneath the skin. Purpura measure 0.3–1 cm (3–10 mm), whereas petechia
Petechia
A petechia is a small red or purple spot on the body, caused by a minor hemorrhage ."Petechiae" refers to one of the three major classes of purpuric skin conditions. Purpuric eruptions are classified by size into three broad categories...
e measure less than 3 mm, and ecchymoses
Ecchymosis
An ecchymosis is the medical term for a subcutaneous purpura larger than 1 centimeter or a hematoma, commonly called a bruise. It can be located in the skin or in a mucous membrane.-Presentation:...
greater than 1 cm.
This is common with typhus
Typhus
Epidemic typhus is a form of typhus so named because the disease often causes epidemics following wars and natural disasters...
and can be present with meningitis
Meningitis
Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs...
caused by meningococcal
Neisseria meningitidis
Neisseria meningitidis, often referred to as meningococcus, is a bacterium that can cause meningitis and other forms of meningococcal disease such as meningococcemia, a life threatening sepsis. N. meningitidis is a major cause of morbidity and mortality during childhood in industrialized countries...
meningitis or septicaemia
Sepsis
Sepsis is a potentially deadly medical condition that is characterized by a whole-body inflammatory state and the presence of a known or suspected infection. The body may develop this inflammatory response by the immune system to microbes in the blood, urine, lungs, skin, or other tissues...
. In particular, meningococcus, a Gram-negative
Gram-negative
Gram-negative bacteria are bacteria that do not retain crystal violet dye in the Gram staining protocol. In a Gram stain test, a counterstain is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color...
diplococci organism, releases endotoxin when it lyses. Endotoxin activates the Hageman factor (clotting factor XII), which causes disseminated intravascular coagulation. The DIC
Disseminated intravascular coagulation
Disseminated intravascular coagulation , also known as disseminated intravascular coagulopathy or consumptive coagulopathy, is a pathological activation of coagulation mechanisms that happens in response to a variety of diseases. DIC leads to the formation of small blood clots inside the blood...
is what appears as a rash on the affected individual.
Classification
Purpura is a common and nonspecific medical sign; however, the underlying mechanism commonly involves one of the following:- Platelet disordersPlateletPlatelets, or thrombocytes , are small,irregularly shaped clear cell fragments , 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes. The average lifespan of a platelet is normally just 5 to 9 days...
(Thrombocytopenic purpuraThrombocytopenic purpuraThrombocytopenic purpura are purpura associated with a reduction in circulating blood platelets which can result from a variety of causes.- Types :...
)- Primary thrombocytopenic purpuraIdiopathic thrombocytopenic purpuraIdiopathic thrombocytopenic purpura is the condition of having an abnormally low platelet count of no known cause . As most incidents of ITP appear to be related to the production of antibodies against platelets, immune thrombocytopenic purpura or immune thrombocytopenia are terms also used to...
- Secondary thrombocytopenic purpura
- Post-transfusion purpuraPost-transfusion purpuraPost-transfusion purpura is an adverse reaction to a blood transfusion or platelet transfusion that occurs when the body produces alloantibodies to the introduced platelets' antigens. These alloantibodies destroy the patient's platelets leading to thrombocytopenia, a rapid decline in platelet count...
- Primary thrombocytopenic purpura
- Vascular disorders (Nonthrombocytopenic purpuraNonthrombocytopenic purpuraNonthrombocytopenic purpura is a type of purpura not associated with thrombocytopenia.Examples/causes include:* Henoch-Schönlein purpura.* Hereditary hemorrhagic telangiectasia* Congenital cytomegalovirus...
)- Microvascular injury, as seen in senile (old age) purpura, when blood vessels are more easily damaged
- Hypertensive states
- Deficient vascular support
- VasculitisVasculitisVasculitis refers to a heterogeneous group of disorders that are characterized by inflammatory destruction of blood vessels. Both arteries and veins are affected. Lymphangitis is sometimes considered a type of vasculitis...
, as in the case of Henoch-Schönlein purpuraHenoch-Schönlein purpuraHenoch–Schönlein purpura is a disease of the skin and other organs that most commonly affects children. In the skin, the disease causes palpable purpura ; often with joint and abdominal pain...
- Coagulation disordersCoagulopathyCoagulopathy is a condition in which the blood’s ability to clot is impaired. This condition can cause prolonged or excessive bleeding, which may occur spontaneously or following an injury or medical and dental procedures.The normal clotting process depends on the interplay of various proteins in...
- Disseminated intravascular coagulationDisseminated intravascular coagulationDisseminated intravascular coagulation , also known as disseminated intravascular coagulopathy or consumptive coagulopathy, is a pathological activation of coagulation mechanisms that happens in response to a variety of diseases. DIC leads to the formation of small blood clots inside the blood...
(DIC) - ScurvyScurvyScurvy is a disease resulting from a deficiency of vitamin C, which is required for the synthesis of collagen in humans. The chemical name for vitamin C, ascorbic acid, is derived from the Latin name of scurvy, scorbutus, which also provides the adjective scorbutic...
(vitamin CVitamin CVitamin C or L-ascorbic acid or L-ascorbate is an essential nutrient for humans and certain other animal species. In living organisms ascorbate acts as an antioxidant by protecting the body against oxidative stress...
deficiency) - defect in collagen synthesis due to lack of hydroxylation of procollagen. It results in weakened capillary walls and cells.
- Disseminated intravascular coagulation
- Meningococcemia
- CocaineCocaineCocaine is a crystalline tropane alkaloid that is obtained from the leaves of the coca plant. The name comes from "coca" in addition to the alkaloid suffix -ine, forming cocaine. It is a stimulant of the central nervous system, an appetite suppressant, and a topical anesthetic...
ingestion (according to a medical article by Francie Diep that appeared the September 2011 issue of Scientific AmericanScientific AmericanScientific American is a popular science magazine. It is notable for its long history of presenting science monthly to an educated but not necessarily scientific public, through its careful attention to the clarity of its text as well as the quality of its specially commissioned color graphics...
magazine, Dr. Noah Craft, a dermatologist at Harbor-UCLA Medical CenterHarbor-UCLA Medical CenterHarbor–UCLA Medical Center is a 570-bed public teaching hospital located at 1000 West Carson Street within the unincorporated Los Angeles County area of West Carson, California...
who co-authored the paper on it, if the one-time chemotherapy drug and now veterinary de-worming agent levamisoleLevamisoleLevamisole is an anthelminthic and immunomodulator belonging to a class of synthetic imidazothiazole derivatives. It was discovered at Janssen Pharmaceutica in 1966...
is added by predominantly South American traffickers to cocaine because it dilutes, or cuts it, and supposedly makes it cheaper and prolongs the high, it can cause purpura of the ears, face, trunk, or extremities, sometimes needing reconstructive surgeryReconstructive surgeryReconstructive surgery is, in its broadest sense, the use of surgery to restore the form and function of the body, although Maxillo-Facial Surgeons, Plastic Surgeons and Otolaryngologists do reconstructive surgery on faces after trauma and to reconstruct the head and neck after cancer.Other...
)
There are also cases of psychogenic purpura described in the medical literature, some claimed to be due to "autoerythrocyte sensitization." Other studies suggest, that local (cutaneous) activity of tPA
Tissue plasminogen activator
Tissue plasminogen activator is a protein involved in the breakdown of blood clots. It is a serine protease found on endothelial cells, the cells that line the blood vessels. As an enzyme, it catalyzes the conversion of plasminogen to plasmin, the major enzyme responsible for clot breakdown...
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.
See also
- BruiseBruiseA bruise, also called a contusion, is a type of relatively minor hematoma of tissue in which capillaries and sometimes venules are damaged by trauma, allowing blood to seep into the surrounding interstitial tissues. Bruises can involve capillaries at the level of skin, subcutaneous tissue, muscle,...
- PetechiaPetechiaA petechia is a small red or purple spot on the body, caused by a minor hemorrhage ."Petechiae" refers to one of the three major classes of purpuric skin conditions. Purpuric eruptions are classified by size into three broad categories...
- Ecchymoses
- Purpura secondary to clotting disordersPurpura secondary to clotting disordersPurpura secondary to clotting disorders are purpura which occur due to hereditary disorders of blood coagulation in which there is a deficiency or qualitative abnormality of a single coagulation factor, as in hemophilia or von Willebrand's disease....
- Food-induced purpuraFood-induced purpuraFood-induced purpura is a skin condition that may result from ingestion of tartrazine dye, benzoates, and food containing Escherichia coli O157:H7....
External links
- Evaluating the Child with Purpura from American Academy of Family PhysiciansAmerican Academy of Family PhysiciansThe American Academy of Family Physicians was founded in 1947 to promote the science and art of family medicine. It is one of the largest medical organizations in the United States, with over 100,000 members...