Skin inflammation. Light micrograph of a section through skin showing inflamed capillaries (lower left and upper right) caused by capillaritis, also known as pigmented purpurea. The capillary walls become inflamed and blood cells leak out into the surrounding tissues. This leads to reddish brown patches on the surface of the skin. Capillaritis may be caused by an allergic reaction to medication, food additives or a viral infection. There is no known cure except avoidance of possible allergens.