View source for Purpura

{{for|the American poet|Lia Purpura}}
{{Infobox_Disease |
  Name           = {{PAGENAME}} |
  Image          = Purpura.jpg |
  Caption        = |
  DiseasesDB     = 25619 |
  ICD10          = {{ICD10|D|69||d|65}} |
  ICD9           = {{ICD9|287}} |
  ICDO           = |
  OMIM           = |
  MedlinePlus    = |
  eMedicineSubj  = |
  eMedicineTopic = |
  MeshID         = D011693 |
}}
[[Image:Purpura1.jpg|thumb|right|200px|Petechial spots over the back]]
'''Purpura''' (from the 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. Purpura measure 0.3-1 cm, whereas [[petechia|petechiae]] measure less than 3 mm, and [[Ecchymosis|ecchymoses]] greater than 1 cm.<ref name=Robbins>{{cite book |author=Mitchell RS; Kumar V; Robbins SL; Abbas AK; Fausto N |title=Robbins basic pathology (8th ed.) |publisher=[[Elsevier|Saunders/Elsevier]] |location= |year=2007 |pages= 10–11 |isbn=1-4160-2973-7 |oclc= |doi= |accessdate=}}</ref>

This is common with [[typhus]] and can be present with [[meningitis]] caused by [[Neisseria meningitidis|meningococcal]] meningitis or [[Sepsis|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 [[Disseminated intravascular coagulation|DIC]] 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|Platelet disorders]] ([[Thrombocytopenic purpura]])
**[[idiopathic thrombocytopenic purpura|Primary thrombocytopenic purpura]]
**Secondary thrombocytopenic purpura
**[[Post-transfusion purpura]]
*Vascular disorders ([[Nonthrombocytopenic purpura]])
**Microvascular injury, as seen in senile (old age) purpura, when blood vessels are more easily damaged
**[[Hypertensive]] states
**Deficient vascular support
**[[Vasculitis]], as in the case of [[Henoch-Schönlein purpura]] or[?] Hepatitis C
*[[Coagulopathy|Coagulation disorders]]
**[[Disseminated intravascular coagulation]] (DIC)
**[[Scurvy]] ([[vitamin C]] deficiency) - defect in collagen synthesis due to lack of hydroxylation of procollagen. It results in weakened capillary walls.
*[[Meningococcal disease|Meningococcemia]]

There are also cases of [[psychogenic]] purpura described in the medical literature,<ref name="pmid10069314">{{cite journal |author=Anderson JE, DeGoff W, McNamara M |title=Autoerythrocyte sensitization (psychogenic purpura): a case report and review of the literature |journal=Pediatric emergency care |volume=15 |issue=1 |pages=47–8 |year=1999 |pmid=10069314 |doi=10.1097/00006565-199902000-00014}}</ref> some claimed to be due to "autoerythrocyte sensitization." Other studies<ref name="pmid8340191">{{cite journal |author=Lotti T, Benci M, Sarti MG, Teofoli P, Senesi C, Bonan P, et al. |title=Psychogenic purpura with abnormally increased tPA dependent cutaneous fibrinolytic activity |journal=Int J Dermatol |volume=32| issue=7 |pages=521–3 |year=1993 |pmid=8340191 |doi=10.1111/j.1365-4362.1993.tb02840.x}}</ref> suggest, that local (cutaneous) activity of [[Tissue plasminogen activator|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.

==See also==
*[[Bruise]]
*[[Petechia]]
*[[Ecchymoses]]
*[[Purpura secondary to clotting disorders]]
*[[Food-induced purpura]]

==References==
<references/>

==External links==
* [http://www.aafp.org/afp/20010801/419.html Evaluating the Child with Purpura] from [[American Academy of Family Physicians]]

{{Myeloid hematologic disease}}
{{Hemodynamics}}
[[Category:Dermatologic terminology]]
[[Category:Medical signs]]

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