Capillaritis

Capillaritis is the name given to a harmless skin condition in which there are reddish-brown patches caused by leaky capillaries. It is also known as pigmented purpura.

The capillaries are small blood vessels near to the skin surface. For unknown reasons they sometimes become inflamed, although a true vasculitis is not seen on skin biopsy. Blood cells may pass through small gaps that arise between the cells, which make up the capillary walls. The result is tiny red dots appear on the skin, described as cayenne pepper spots. They group together to form a flat red patch, which becomes brown and then slowly fades away over weeks to months.

Capillaritis

Schamberg purpura	Close-up of lower back
Capillaritis	Lichen aureus

More images of capillaritis ...

What is the cause of capillaritis?

The cause of capillaritis is usually unknown. Occasionally it arises as a reaction to a medication; many different drugs have been occasionally associated with capillaritis. In others a food additive or a viral infection may be responsible. Capillaritis may also develop after exercise.

Clinical features

There are several descriptive types of capillaritis. They are often named after the dermatologist who first described them

• Schamberg disease (progressive pigmented purpura).
  This is the most common type of capillaritis. Crops of red-brown flat patches with cayenne pepper spots on their borders appear for no apparent reason. Although most common on the lower legs, Schamberg can arise on any part of the body. It is usually irregularly distributed on both sides with few or many patches. There are no symptoms.
• Itching purpura
  This appears similar to Schamberg disease, but itches.
• Gougerot-Blum (pigmented purpuric lichenoid dermatosis)
  This form of capillaritis is less common. The patches are thickened and itchy, rather like eczema.
• Majocchi's purpura (purpura annularis telangiectodes)
  In this condition there are dilated capillaries as well as brown patches and cayenne spots. The patches gradually spread outwards.
• Contact allergy
  Capillaritis has been reported to be due to khaki clothing dye and rubber. It only affects skin in contact with the responsible material.
• Lichen aureus
  Lichen aureus is a solitary brown-yellow patch that is very persistent. It often overlies a varicose vein.
• Exercise-induced capillaritis
  Crops of small red spots may develop on the ankles following prolonged or vigorous exercise (e.g. 18 holes of golf, tramping or dancing), especially during warm weather. The spots fade to brown within a few days and eventually disappear. A burning sensation may occur as the new lesions appear.

Treatment

There is no known cure for most cases of capillaritis. It can disappear within a few weeks, recur from time to time, or frequently persist for years.

• Consider if a medication could be the cause: discontinue it for several months to find out if the capillaritis improves
• Try avoiding food preservatives and artificial colouring agents. Return to a normal diet if there is no improvement after several months.
• Topical steroids can be helpful for itching but rarely clear the capillaritis.
• If the lower leg is affected, consider wearing graduated compression elastic hose.
• Currently available lasers are not particularly helpful for this condition.