Petechia Or Purpura

Medically reviewed by The Dermatologists and written by  Dr. Aayushi Shah

 

  • Petechiae are 1-2 mm in size, purpura are more than 0.5 cm.
  • Ecchymosis are larger, deeper collections of blood. 
  • They are non-blanchable
  • Can occur due to a wide variety of causes, broadly classified as platelet related (thrombogenic) and non-platelet related or vascular.
  • Sometimes suggestive of serious systemic illnesses
  • Requires medical attention and workup in most cases

 

ICD10 Code – D69

 

Purpura is the term used to describe a reddish discoloration of the skin or mucous membranes due to extravasation of red blood cells from blood vessels into the surrounding tissue. Petechiae are circumscribed deposits of blood (that is, small purpuric lesions) which are less than 0.5 cm in size (usually 1 to 2 mm). Purpura, on the other hand, are greater than 0.5 cm in size. The appearance of purpura is quite characteristic; they do not blanch with pressure.

Ecchymoses (bruises) are larger, deeper collections of blood under the skin (>1 cm in size). This extravasated blood usually breaks down and changes colour over a few weeks, from red to purple, brown, blue and even green, before resolving without leaving any permanent marks.

Purpura is a sign rather than a diagnosis, and its management consists of finding the underlying cause. The causes of purpura can be classified into vascular (non-thrombocytopenic) and thrombocytopenic disorders.

The causes of petechiae and ecchymoses can often overlap. Low platelet levels (thrombocytopenia) usually causes petechiae. However, more extensive bleeding may occur when the platelets fall to extremely low levels. Blood clotting disorders cause ecchymosis rather than petechiae.

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Symptoms

Petechiae and purpura present as reddish spots underneath the skin, which do not blanch on pressure or occlusion, and which may or may not be raised or palpable. They may be localised or generalised, depending on the underlying cause. They may or may not be associated with other symptoms such as bleeding, fever, bodyache, joint pains, etc.

Petechiae and purpura can be associated with a constellation of skin and systemic diseases, thus, usually many relevant investigations need to be performed to reach a final diagnosis.

Some specific types and causes of purpura are as follows:

 

  1. Palpable purpura – This is a certain type of purpura which can be felt with the fingers, this occurs in certain disorders such as vasculitis.
  2. Senile Purpura – Purple patches seen in aging skin after minor shear forces. This occurs due to loss of skin collagen with advancing age. Accompanied by signs such as atrophy of skin, dryness, etc. More evident in people taking oral or inhaled steroids.
  3. Meningococcal petechiae – A patient with meningococcemia may develop a petechial rash, or even a severe purpura fulminans. Development of these signs is usually a poor prognostic indicator.
  4. Blue toe syndrome: Usually seen in older men after undergoing a vascular invasive procedure such as an angiography or angioplasty. It can occur due to a variety of causes, including certain thrombotic conditions.
  5. Drug-induced purpura – This can occur due to drugs such as steroids, warfarin, aspirin, etc.
  6. Pigmented purpuric dermatoses – A characteristic discoloration seen in the lower limbs, due to hemosiderin deposition after extravasation of RBCs from blood vessels.
  7. Pinch Purpura – This is seen in amyloidosis, due to its typical appearance on the cheeks.

 

What can I do?

If you think you have petechiae or purpura, consult your doctor as soon as possible, as it can often be a sign of an underlying illness. In addition, it may be necessary to review any other associated symptoms, recent illnesses, as well as check your medications for any irregularities. Over-the counter creams or tablets are not very helpful in the treatment of purpura.

Should I seek medical care?

Yes, it is very important to seek medical advice in a suspected case of petechiae or purpura, as they are associated with a wide variety of illnesses.

 

Treatment

Investigations: Cases with purpura may require an extensive workup, based on the clinical picture and other symptoms. A full Blood Count, Platelet Count, Coagulation Profile, Erythrocyte Sedimentation Rate, INR test are some of the investigations which may be performed. Additionally, a sepsis screen, bone marrow examination, urine examination, are some of the other tests which may be needed.

 

In some cases such as the pigmented purpuric dermatoses in the lower legs, where the underlying cause is obvious and there are no other symptoms, no investigations may be required. However, a skin biopsy may be needed to confirm the diagnosis in such cases.

 

The treatment depends on the severity of symptoms and the underlying cause, which needs to be treated for the purpura to resolve. Some varieties of purpura, such as Henoch Scholein Purpura, are self-resolving without any treatment, and only symptomatic care may be needed.

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Sources:

  1. Habif, Thomas P. Clinical dermatology. 5th ed. Mosby Elsevier. 2010.
  2. Griffiths C EM, Barker J, Bleiker T, Chalmers R, Creamer D. Rook’s Textbook of Dermatology. 9th Ed. Wiley Blackwell. 2016.
  3. Purpuric Rashes. What causes purpuric rashes? Information. | Patient

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