Purpuric Rashes - Symptoms and Causes

What are the symptoms of a purpuric rash?

A purpuric rash is not a disease but it is caused by conditions that result in blood leaking into the skin and other body surfaces.

The rash looks like little red spots on the skin. It's easy to recognise because - unlike other spotty rashes - the spots don't fade when you press them. The best way to do this is with a drinking glass or other see-through object like a plastic ruler.

PURPURA

There are so many different causes of a purpuric rash it's difficult to list all the symptoms that may occur due to the underlying illness. However, common symptoms you may notice occurring with the rash include:

  • Spots inside the mouth.
  • Blisters (which may be clear or yellow like little boils).
  • Tenderness in the area of the rash.
  • A high temperature (fever).
  • Feeling under the weather.
  • Joint pains.
  • Tummy pains.

What causes a purpuric rash?

There are many different causes of purpuric rashes. Several of them can be grouped into those caused by lack of platelets and those in which the platelets are present in normal numbers. Conditions in which the platelet numbers are normal are called non-thrombocytopenic. Those in which the platelet numbers are low are called thrombocytopenic.

Non-thrombocytopenic causes

  • Conditions you are born with, such as:
  • Conditions acquired after you were born, such as:
    • Severe infections such as sepsis, infection with one of the germs that cause meningitis (meningococcus).
    • Allergy-based conditions such as Henoch-Schönlein purpura.
    • Disorders of the connective tissue that connects and binds other bits of the body together, such as systemic lupus erythematosus and rheumatoid arthritis.
    • As a side effect of medicines such as steroids and sulfonamides (antibiotics).
    • Other causes, such as ageing of the skin, injury (trauma), lack of vitamin C (scurvy) and poor blood supply, especially to the legs.

Thrombocytopenic causes

  • Conditions resulting from problems with platelet production, such as:
    • Bone marrow failure - for example:
      • Leukaemia.
      • Aplastic anaemia (anaemia caused by problems with production of the platelets and other blood cells by the bone marrow).
      • Myeloma.
      • Cancer deposits replacing the bone marrow.
      • Medicines such as co-trimoxazole (an antibiotic) and chemicals.
  • Conditions that increase the breakdown of platelets, such as:
  • Conditions affecting the blood clotting (coagulation) system, such as:
    • Disseminated intravascular coagulation which causes excessive blood clotting in small blood vessels).
    • Haemolytic uraemic syndrome (destruction of blood cells associated with kidney problems).
  • Enlarged spleen.
  • Conditions causing dilution of the platelets, such as rapid transfusion of large quantities of stored blood.

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  • Purpura; University of Maryland Medical Centre
  • Maher GM; Immune thrombocytopenia. S D Med. 2014 Oct 67(10):415-7.
  • Purpura; Internal Medicine Reference
Author:
Dr Laurence Knott
Peer Reviewer:
Prof Cathy Jackson
Document ID:
29413 (v1)
Last Checked:
08 July 2017
Next Review:
07 July 2020

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.