What is vasculitis?
Vasculitis of the skin is inflammation of the blood vessels in the skin. There are different types of vasculitis, and the condition can present with different kinds of skin abnormalities. Its presentation depends partly on the size of the skin blood vessels that have become inflamed.
In most cases of vasculitis, the inflammation remains confined to the blood vessels in the skin. In a small percentage of cases, blood vessels in other organs of the body also become inflamed. This form of vasculitis is more dangerous than vasculitis confined to the skin.
The different types of vasculitis
The most common form of vasculitis is leucocytoclastic vasculitis. This article concerns that form of vasculitis.
There are also several rarer forms of vasculitis, such as polyarteritis nodosa, Churg–Strauss syndrome and Wegener’s granulomatosis, which are described here as forms involving large vessels, and Henoch–Schönlein vasculitis, urticarial vasculitis and erythema elevatum diutinum, which involve small vessels.
Leucocytoclastic vasculitis
What causes leucocytoclastic vasculitis?
There are several possible causes of this form of vasculitis. The main ones are:
Infections
Both viruses and bacteria may play a part in causing vasculitis. There are three possible mechanisms:
- The microorganisms directly damage the vessel wall.
- The microorganisms prompt the immune system to produce antibodies which, in turn, unintentionally cause inflammation of the vessel wall.
- Complement, the proteins in the blood that play a part in defence against microorganisms, damages the vessel walls.
Medicines
Medicines can also cause inflammation of the blood vessels. Antibiotics, diuretics, or water tablets, and certain blood thinners are particularly well known as causes of vasculitis.
Autoimmune diseases
In autoimmune diseases, such as lupus erythematosus and rheumatoid arthritis, the immune system circulates antibodies against the body’s own cells. In some cases, these antibodies are also directed against the blood vessels and vasculitis may develop.
Cancer
In cancer, the immune system may try to attack the cancer cells. It then produces antibodies directed against the cancer which may sometimes cause vasculitis at the same time.
What does it look like?
In leucocytoclastic vasculitis, red and purple spots and bumps appear on the skin, particularly on the lower legs, but sometimes also on the thighs and elsewhere on the skin. These areas do not disappear when the skin is pressed. This is because blood has escaped from the small blood vessels as a result of the inflammation.
These areas are called petechiae when they are small and ecchymoses when they are larger than approximately 1 cm. Gravity also plays an important part in the development of vasculitis and in blood cells escaping from the vessels. This is why most of the areas, and the largest ones, are seen mainly on the lower legs.
How is the diagnosis made?
For a dermatologist, leucocytoclastic vasculitis is not difficult to diagnose from its clinical appearance. If there is doubt, a small tissue sample, or biopsy, may be taken for further examination.
The main question is usually what has caused the inflammation, and the dermatologist will want to make sure that vasculitis is not present in other organs. Additional blood tests are therefore carried out. These include a general screen, tests for autoimmune antibodies such as ANA and ANCA, and tests for infections. The urine is also checked.
In many cases, the cause of the condition will not be found despite thorough investigation.
How is vasculitis treated?
It is important to rest during the initial phase of the condition. The skin must also be protected from damage because inflammation of the blood vessels makes the affected skin very fragile. A protective dressing may be applied if necessary.
Corticosteroids, such as prednisone, can calm the inflammation. Sometimes a course of a few days is sufficient to stop the inflammatory process; in other cases, longer treatment with corticosteroids on a tapering schedule is needed.
If the severe disruption of the skin’s blood supply causes ulcers at the sites of the ecchymoses, good wound care will also be required.
In most cases, the inflammation subsides and does not return. Persistent vasculitis or recurrent episodes of inflammation require a renewed investigation of the cause.
Related topics
- Skin – anatomy and function
- Urticarial vasculitis
- Golfer's vasculitis
- Red patches on the skin
- Skin rash