Purpura Vs Ecchymosis

Introduction

Medical language can be very complicated, with different words describing almost the same thing or technical terms being used to describe commonplace symptoms. Read on to discover the symptoms of purpura and ecchymosis, how they are similar, how they are different, and what to do about them. 

What is ‘purpura’?

Purpura is a medical term to describe a symptom, and in itself is not a diagnosis. Purpura are patches of red, purple or brown discolouration caused by leaking small blood vessels.¹ Purpura most commonly appears under the skin or in mucous membranes, such as the lining of the mouth.¹ 

Purpura is generally caused by a reduced number of platelets in the blood, meaning that blood is more prone to leaking out of small blood vessels.¹ There are a number of causes not related to platelets, and they are discussed further below. 

What is ‘ecchymosis’?

Similarly to purpura, ecchymosis is not a diagnosis but describes a symptom of a condition. Simply put, an ecchymosis is what we would commonly describe as a bruise, and is the same as a contusion (a collection of blood outside blood vessels).² Ecchymosis is most commonly caused by the breakage of blood vessels during traumatic damage to an area of skin.² Trauma is not the only cause of ecchymosis, and it can be a symptom of another underlying medical condition. 

Clinical presentation

As you can see, purpura and ecchymosis are both caused by blood leaking from vessels and becoming visible on the skin’s surface, but for different reasons. There are also important differences in their physical presentation that help name them and aid further investigation.

Size and appearance 

Size

It is important to know that although purpura may look like a bruise, it is not a bruise, especially when there has been no trauma to the area, which can be a sign of an underlying condition.¹ Purpura covers a smaller surface area in comparison to ecchymosis, measuring between four and ten millimetres (mm) in diameter, whereas ecchymosis is larger than 10 mm, or one centimetre (cm) in diameter.³ Smaller than purpura are areas of bleeding called petechiae, which measure under 4 mm in diameter.³ 

Appearance 

As well as size, purpura and ecchymosis have morphological (shape) differences. Purpura can be described as ‘blood spots’ close to the surface of the skin.¹ Large areas of purpura can arise and could be mistaken for ecchymosis, but their individual size and shallow depth would all point to the former. As well as being larger, ecchymosis develops deeper under the skin and can resemble general skin discolouration rather than spots.²

Colour changes 

Both purpura and ecchymosis can be similar colours as they develop, especially if they are red or brown in colour.^1,2 Owing to their depth, ecchymosis can also appear darker and either black or purple in colour.² An ecchymosis will change colour as it ages, sometimes yellow or brown (or even green!) before eventually disappearing as the damaged blood vessels heal and the old blood is removed.² Purpura can also disappear, depending on their cause, and can also change colour a number of times before the blood is reabsorbed.⁴ This is not the best way to differentiate between them but may be useful in combination with other signs.

Physical examination 

As ecchymosis is most commonly related to an injury, there may be some swelling and pain or tenderness related to the area when it is examined or touched.² Purpura is unlikely to be painful¹, but there can be some sensitivity or swelling to the area, especially where inflamed blood vessels are responsible for the symptoms.⁴

Distribution on the body 

Purpura and ecchymosis have different distributions on the skin. Purpura can be found anywhere on the skin, including on the mucous membranes such as inside the mouth. Their location is not necessarily related to their cause.¹ On the other hand, ecchymosis is related to the location of an injury and will be more commonly found on arms and legs, as well as injection sites and body parts that have recently been operated on.² 

Pathophysiology

Purpura

Blood vessel structure 

Purpura occurs when blood vessels leak into the tissue surrounding them, known as extravasation.¹ Damaged and inflamed blood vessels can make this more likely, and weakened vessels can be a natural result of ageing, but can also be caused by a connective tissue condition, such as Ehlers-Danlos syndrome.¹ Vasculitis (inflammation of the blood vessel tissues), can also make leaking more likely.¹ 

Platelet and coagulation factors

Blood is a complex component of the body, and has a number of chemical and cell mechanisms to ensure that it is neither too thick nor too thin in consistency.⁵ Platelets, also known as thrombocytes, play a crucial role in blood clot formation - and many causes of purpura are classified according to whether they are caused by low platelets (thrombocytopenic) or not (non-thrombocytopenic). The cause of low platelets can be due to reduced production of platelets or high levels of platelet destruction.

Some thrombocytopenic causes include⁶

• Medications that can lower blood platelet counts - such as ibuprofen, statins and heparin-induced thrombocytopenia 
• Bloodstream infections 
• Autoimmune conditions - where the immune system attacks platelet production such as lupus and idiopathic thrombocytopenic purpura (also known as ITP)
• Conditions that affect the bone marrow, such as leukaemia 

Clotting factors are proteins found within the blood and work together to ensure blood clots are regulated and do not take place excessively.⁵ Deficiencies in clotting factors in conditions such as haemophilia can make purpura more likely.⁵

Other medical conditions

There are many other conditions that can cause purpura but are not related to platelet function and these can be described as non-thrombocytopenic causes.

These include¹

• Scurvy - vitamin C deficiency
• Amyloidosis 
• Infection with cytomegalovirus (CMV) or rubella before birth
• Steroid use 
• Injury 

Ecchymosis

Trauma-related blood vessel damage

Bruising can be caused by damage to blood vessels via an accident or trauma. When a blood vessel is broken, blood can collect in the tissues surrounding the damaged vessel causing the discolouration associated with bruising.² This in turn can cause the development of a haematoma when enough blood collects underneath the skin.⁷ 

Platelet and coagulation factors 

Similarly to purpura, ecchymosis can be caused by a low level of platelets in the blood, or deficient levels of clotting factors.⁷ The lack of platelets or clotting factors stops blood from leaking out of a damaged blood vessel, and so bruising can occur.⁷

Relationship to ageing

As we age, our skin becomes thinner and blood vessel walls are not as strong as before, increasing the likelihood of injury causing a breakage.⁷

Diagnostic evaluation

As mentioned previously, both purpura and ecchymosis are symptoms and not diagnoses in themselves, so it is important to assess for a potential underlying cause. These diagnostic tools may be used to diagnose the underlying causes of purpura or ecchymosis.

Clinical history and physical examination

A healthcare professional will want to ask about your symptoms, anything that happened before they appeared, as well as any other symptoms they might feel are relevant.¹ They will ask about the medications you take and other medical conditions you have. This will help build a picture of possible causes of this new symptom.

A physical examination of the affected skin will also happen so that the size and location of the purpura or ecchymosis can be assessed.^1,2

Blood tests

Depending on the findings from the clinical history and examination, your healthcare professional may deem it appropriate to carry out blood tests to assess your platelet levels and coagulation profile.^1,2 If you take medication that alters your blood clotting, such as warfarin, they may also carry out specific tests related to these.

Imaging

In the case where ecchymosis is suspected to be caused by trauma, your healthcare professional may recommend an x-ray to rule out any broken bones underlying the bruising.²

Skin biopsy

In the case of purpura, especially when believed to be related to vasculitis, a skin biopsy may be taken as a way to diagnose the condition.⁸

Treatment

Once a cause has been determined for either purpura or ecchymosis, there are a number of steps that can be taken to treat the symptoms. As with any symptom, if an underlying cause can be found then this will need treatment. There are many treatments that are possible for either purpura or ecchymosis, but some of the more common are listed below.^9,10

Purpura 

• Steroid treatment
• Immune-suppressing medications in autoimmune conditions
• Medications to rapidly increase platelet numbers 
• Blood transfusion 

Ecchymosis

• Fixing any associated broken bones, if found 
• Large haematomas may need to be drained
• Pain relief 
• Use of the R.I.C.E. method to manage the effect of the injury
  • Rest the affected area
  • Ice or a cold pack is applied to the injury as soon as possible, making sure ice is wrapped up and not applied directly to the area
  • Compression of the injured area to reduce swelling 
  • Elevate the injury if possible 

Prognosis

Purpura

There are so many causes of purpura that the outcome and treatment required will depend on the condition underlying them. The conditions underpinning purpura can progress to further and more severe bleeding, so prompt assessment and treatment are essential to ensure symptoms do not worsen.¹

Ecchymosis

In cases of traumatic bruising, ecchymosis will fade over weeks to months, depending on the severity of the bruising.²

Please seek prompt medical attention if you experience:^1,2

• Bruising around the eye and any vision problems 
• Unexplained bruising 
• Bruising that does not change colour within two weeks
• Repeated bruising 
• A lump underlying a bruise or any painful swelling with bruising
• Prolonged pain after a bruise develops
• Any other signs of bleeding - nosebleeds or blood in your urine as examples

Summary

As you can see, the term bruise can include a number of symptoms and in turn a number of underlying diagnoses.

Although purpura and ecchymosis share some common causes, ecchymosis is primarily caused by a trauma whilst purpura originates from an underlying medical condition. Both normally differ in their appearance, size and location on the body. The colour of the marks does not help as much with identifying one from the other, and ultimately professional advice will need to be sought, especially if there has been no injury related to the bruising.

Ascertaining the underlying cause of both purpura and ecchymosis includes a detailed clinical and medication history with a physical examination. Blood tests may also be required to rule out blood clotting issues caused by low platelets or coagulation factor deficiencies. Depending on clinical history and examination, your healthcare provider may recommend further diagnostic tests.

There is a vast range of treatments and outcomes possible for either type of bruising and so it is essential to contact your healthcare professional for an assessment to understand the causes and treatment specifically for you. 

It is very important to seek prompt medical attention if you experience any unexplained bruising, visible bleeding, pain, or hard swelling associated with bruising. Repetitive bruising to the same areas, very large bruises, and any bruising that doesn’t fade over time also need to be assessed as soon as possible.