[Cutaneous alterations in vasculitides : Part 2: Special aspects of diseases of large, medium and small vessels].

Cutaneous vasculitides present with typical clinical signs depending on the size and distribution of the affected vessels. Since there are no large vessels in the skin, giant cell arteritis and Takayasu's arteritis only rarely lead to cutaneous symptoms. The classical systemic polyarteritis nodosa (PAN) is very rare. More frequent is cutaneous PAN presenting with a typical localized livedo racemosa and palpable subcutaneous nodules. The ANCA-associated vasculitides, which belong to the small vessel vasculitides, usually show systemic involvement and manifest on the skin with a diverse picture. Immune complex vasculitides are characterized by deposition of immunoglobulins on the walls of small vessels. The most common form is IgA vasculitis with the cardinal symptoms of palpable, round or oval and partially branched (retiform) purpura and a clear predilection for the legs. Serum disease is a príme example of systemic immune complex diseases due to large circulating immune complexes. Cryoglobulinemic vasculitis primarily involves small as well as medium sized vessels. Simultaneous involvement of vessels of different sizes is characteristic for vasculitis in systemic lupus erythematosus (SLE), Sjögren's syndrome, rheumatoid arthritis and sarcoidosis. Recurrent macular vasculitis in hypergammaglobulinemia is an episodic macular vasculitis of the small blood vessels. Bacteremic vasculitis of the small vessels (without direct microbial infection of the vessel wall) can typically also affect capillaries of dermal papillae and is usually accompanied by a disseminated intravascular coagulation (DIC). In some cases more than one distinct cutaneous vasculitis can occur in the same patient.