What is cutaneous vasculitis?
Cutaneous vasculitis is a group of disorders in which there are inflamed blood vessels in the skin. These may include capillaries, venules, arterioles and lymphatics.
- Cutaneous vasculitis has several different causes
- There are a wide variety of clinical presentations.
- It is associated with systemic vasculitis in a minority of patients
In most cases an underlying cause is not found and the disease is self-limiting.
Classification of cutaneous vasculitis
- Progressive pigmented purpura: the most common form of capillaritis
- Itching purpura
- Pigmented purpuric lichenoid dermatosis
- Purpura annularis telangiectodes
- Contact allergy
- Lichen aureus
Small vessel vasculitis
- Idiopathic cutaneous small vessel vasculitis
- Drug or infection-induced hypersensitivity vasculitis
- Henoch-Schonlein purpura
- Acute haemorrhagic oedema of infancy
- Urticarial vasculitis
- Exercise-induced vasculitis
- Erythema elevatum diutinum
- Malignant atrophic papulosis (Degos)
- ANCA-associated vasculitis
Medium vessel vasculitis
Large vessel vasculitis
- Temporal arteritis
- Takayasu disease
Who gets cutaneous vasculitis?
Cutaneous vasculitis can affect people of all ages and races. Some types of vasculitis have predilection for certain age groups.
- Acute haemorrhagic oedema affects infants
- Henoch Schonlein purpura affects children
- Hypersensitivity vasculitis affects adults
- Older people are more likely to have diseases and medications that are potential causes of small vessel vasculitis
What causes vasculitis?
Many different insults may cause an identical inflammatory response within the blood vessel wall. Three main mechanisms are proposed.
- Direct injury to the vessel wall by bacteria or viruses
- Indirect injury by activation of antibodies
- Indirect injury through activation of complement, a group of proteins in the blood and tissue fluids that attack infection and foreign bodies.
What are the clinical features of vasculitis?
Clinical presentation of cutaneous vasculitis mainly depends on the size of the inflamed blood vessel.
- Capillaritis presents as pigmented purpura, characterised by petechiae resolving with haemosiderin deposition.
- Small vessel vasculitis is characterised by palpable purpura.
- Medium vessel vasculitis is associated with nodules and livedo reticularis.
- Large vessel vasculitis infrequently results in cutaneous features.
How is cutaneous vasculitis diagnosed?
In many cases the diagnosis of vasculitis can be made on the basis of its appearance without requiring any further tests. Sometimes a skin biopsy is performed to confirm the diagnosis but this rarely explains what caused it, as vasculitis is the common endpoint of many different events.
Screening tests are requested in most cases of vasculitis to identify any underlying cause and to determine the extent of involvement of internal organs.
What is the treatment for vasculitis?
Treatment depends on the severity of the disease and may include general measures, systemic corticosteroids, and immune modulating agents.
If cutaneous vasculitis is a manifestation of systemic vasculitis then treatment of the systemic disorder is required.
What is the outlook for cutaneous vasculitis?
Vasculitis limited to the skin has a good prognosis with most cases resolving within a period of weeks to months. The vasculitis may recur at variable intervals after the initial episode.
The prognosis of systemic vasculitis is dependent upon the severity of involvement of other organs. If vasculitis affects the kidneys, lungs or brain it can be life-threatening.