What is purpura ?
Purpura refers to a type of disorder which results in the formation of purple or red discolorations on the surface of the skin. Such patches of discolored skin do not lighten even after the application pressure. It is caused due to bleeding beneath the skin.
It measures 3 to 10 mm or 0.3 to 1 cm in size. As compared to purpura, ecchymoses measure greater than 1 cm while petechiae usually tend to be less than 3 mm.
Purpura is a condition that can be commonly found with other disorders such as typhus. It can also be present as a symptom of meningitis that is caused by septicaemia or meningococcal meningitis.
Meningococcus is a Gram-negative diplococci organism that secretes endotoxin at the time of lyses. The Hageman factor or clotting factor XII is then activated by endotoxin. This results in dissemination of intravascular coagulation. Most studies indicate that the DIC is the primary cause of the appearance of purpura rash on the affected patients.
The classification of purpura
There are several different kinds of purpura. In medical literature, the categorization and classification of purpura is usually dependent on the cause and the appearance changes that occur due to the condition. Sometimes, it may be problematic to classify a singular case of purpura due to overlap. As per the underlying cause, one can categorize the different types of purpura in the following ways:
- Primary or idiopathic thrombocytopaenic purpura: This condition results in the destruction of platelets. The cause for such abnormalities is unknown.
- Secondary thrombocytopaenic purpura: The condition is caused due to a number of external or internal factors such as the presence of certain disorders, infections, certain medications or drugs, etc.
Vascular disorders: There may be leakage of blood due to the following factors.
- The intraluminar pressure may get increased
- Damage or injury to the tiny blood vessels
- Diminished or absent vascular support, as in older adults or sun damaged skin. The condition is known as senile purpura
Coagulation disorders: The leakage of blood may be due to:
- Heparin induced thrombocytopaenia: This results in necrosis and purpura necrosis due to the presence of anti-platelet antibodies, which induce platelet plugs resulting in blockage of blood vessels.
- Disseminated intravascular coagulation: This condition can vary from a serious and rapidly life-threatening condition called purpura fulminans, to a comparatively minor or mild disorder
- Warfarin induced necrosis: The blood clots formed due to relative deficiency in protein C can lead to necrosis and purpura.
Symptoms of purpura
Most of the symptoms of purpura vary as per the type of purpura. Some of the generalized signs and symptoms of purpura are as follows:
- There may be presence of petechiae in thrombocytopaenic purpura. Additionally, the condition may also result in some bruising as well as external bleeding.
- Lesions of the blood vessels can result in localized and chronic purpura that comes with an erythematous inflammatory constituent. They generally tend to be clear and very visible. It rarely leads to external bleeding or ecchymoses.
- Disorders of coagulation generally tend to be present as large ecchymoses. There may be external bleeding. There is no presence of petechiae.
Causes of purpura
There are a number of causes that can result in the development of purpura. Some of the causes are discussed below:
- One of the primary causes of purpura is low count of platelets in the blood. The condition is referred to as thrombocytopenia.
- Purpura can also occur if the skin is particularly thin or due to extreme fragility of the blood vessel wall or due to its damage.
- The elderly people are at greater risk to develop senile purpura in the back of the hand and/or on the outer skin surface of the arm
- Steroids deteriorate the connective tissues present in the skin. Hence prolonged treatment with steroid therapy for underlying conditions can result in purpura.
- The presence of certain inflammatory disorders such as vasculitis can result in damage of the blood vessel wall, which eventually leads to the development of purpura. One such example of an inflammatory condition that is present in children is called Henoch Schönlein purpura. This disorder causes a number of symptoms such as joint and abdominal pain, inflammation of the kidneys and elevated purpura, particularly over the limbs and buttocks.
- Individuals who suffer from vitamin C deficiency or from diseases like scurvy can develop purpura, which leads to the development of symptoms such as painful bruising around hair roots and of the legs.
- Since there are many different types of purpura, it is important to first diagnose the underlying cause of the condition. Once the cause is identified, the patient can undergo relevant treatment
- All cases of purpura need to be immediately checked by a health care provider. Individuals who have skin rashes, but do not develop any serious symptoms can opt for a routine check with a doctor. However, those who have skin rashes as well as symptoms that are severe need to immediately seek a physician’s attention for correct diagnosis and treatment.
Here are the photos of purpura, which are red patches caused due to bleeding below the skin.