[Skin manifestations of different forms of vasculitis]

[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.

[Cutaneous alterations in vasculitides : Part 1: Nomenclature, classification and correlation between clinical signs and histological features]

The skin is one of the organs most commonly affected by vasculitis and the only one that is open to direct inspection. Cutaneous vasculitis can be part of a systemic vasculitis, a variant restricted to the skin (e.g. systemic and cutaneous IgA1 vasculitis) or an independent cutaneous form (recurrent macular vasculitis in hypergammaglobulinemia, nodular vasculitis). For the nomenclature and classification of cutaneous vasculitides the scheme of the Chapel Hill Consensus Conference can be used and the vessels mainly affected determine the clinical picture of individual forms of vasculitis. Some cutaneous efflorescences and their distribution are so characteristic for certain forms of vasculitis that they provide diagnostic indications or even diagnostic criteria. A palpable purpura on the legs is typical for involvement of postcapillary venules in the context of immune complex vasculitis. If arterioles or venules in the dermis are additionally affected, the clinical presentation is that of plaques with marginal offshoots and central hemorrhagic blisters or necrosis (retiform purpura). In contrast to the purpura in occluding vasculopathies, which shows no or little surrounding erythema, the purpura in vasculitis is accompanied by an inflammatory erythema. In vasculitides of the arterioles and small-caliber arteries in the subcutaneous tissue, visible or only palpable nodules exist surrounded by an irregular livedo or also retiform purpura. Understanding how vasculitis-induced efflorescence arises and the histological manifestations helps their recognition during physical examinations in daily practice and is an important guide in the diagnosis and classification of vasculitides.

[Cutaneous polyarteritis nodosa: A rare cause of chronic ulcers]

Cutaneous polyarteritis nodosa, a special form of polyarteritis nodosa (PAN) without systemic involvement, is classified as one of the ANCA-negative vasculitides of small and medium-sized vessels. It is a very rare disease with unknown etiology and occurs more commonly in women over the age of 40. Typical skin lesions are subcutaneous nodules, livedo racemosa, and ulcerations. We report the case of a 46-year-old woman presenting to our outpatient department who reported having very painful ulcerations of the lower legs with unknown origin for 6 months.

[Cutaneous symptoms of various vasculitides]

The skin is one of the organs most frequently involved in vasculitides. Cutaneous vasculitis may present (1) part of a systemic vasculitis (e.g., IgA vasculitis), (2) a skin-restricted or skin-dominant variant of the corresponding systemic vasculitis without clinically apparent visceral involvement (e.g., cutaneous IgA vasculitis), or (3) a vasculitis occurring exclusively in the skin (e.g., erythema elevatun diutinum). The clinical symptoms of vasculitides are markedly determined by the size of the predominantly affected blood vessels. Systemic polyarteritis nodosa is regarded as a medium vessel vasculitis and is associated with multiple skin symptoms: (1) vasculitis of digital arteries with ensuing digital infarction, (2) livedo racemosa and subcutaneous nodules, and (3) in some patients even purpura and hemorrhagic macules due to additional small vessel vasculitis. In contrast, in its skin-restricted entity (i.e., cutaneous polyarteritis nodosa), the predominant symptoms are subcutaneous nodules surrounded by livedo racemosa, often on the lower legs. Among small-vessel vasculitides palpable purpura with predilection for the legs is a nearly pathognomonic feature of immune complex vasculitis. Variations in clinical symptoms indicate additional pathophysiological mechanisms or different vascultides: (1) ANCA-associated vasculitides often also entail nodules or sometimes livedo, (2) cryoglobulinemic vasculitis additionally may present with necrosis at cold exposed areas and involvement of vessels of various size, (3) small vessel vasculitis associated with systemic lupus erythematosus or rheumatoid arthritis shows predilection for additional sites (e.g., nailfolds) and also involvement of vessels beyond postcapillary venules, (4) recurrent macular vasculitis in hypergammaglobulinemia also occurs on dependent parts, but shows numerous small hemorrhagic macules instead of palpable purpura, (5) erythema elevatum diutinum begins with brightly red to violaceous plaques at extensor sites, followed by fibrotic nodules. Consequently, cutaneous symptoms provide pivotal clues for further diagnosis and ensuing management of vasculitides.