RESEARCH - The spectrum of skin lesions in RA

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J Cutan Pathol 2003 Jan;30(1):1-10

INTRODUCTION: Rheumatoid arthritis (RA) is an idiopathic arthropathy

syndrome that has a propensity to affect the small joints of the hands and

feet with extra-articular manifestations comprising skin lesions,

neuropathy, pericarditis, pleuritis, interstitial pulmonary fibrosis and a

systemic polyarteritis nodosa (PAN)-like vasculitic syndrome. The most

widely recognized skin lesion is the rheumatoid nodule. Other skin

manifestations are poorly defined.

MATERIALS AND METHODS: Using a natural language search of the authors'

outpatient dermatopathology databases, skin biopsies from 43 patients with

RA were selected for retrospective analysis in an attempt to define the

dermatopathological spectrum of RA and its clinical correlates.

RESULTS: The biopsies were categorized by the dominant histologic pattern,

recognizing that in most cases there were additional minor reaction

patterns. Palisading and/or diffuse interstitial granulomatous inflammation

was the dominant pattern seen in 21 patients; the lesions included nodules,

plaques and papules with a predilection to involve skin over joints. Besides

interstitial histiocytic infiltrates and variable collagen necrobiosis,

these cases also showed interstitial neutrophilia, vasculitis and

pauci-inflammatory vascular thrombosis. The dominant morphology in 11 other

patients was vasculopathic in nature: pauci-inflammatory vascular

thrombosis, glomeruloid neovascularization, a neutrophilic vasculitis of

pustular, folliculocentric, leukocytoclastic or benign cutaneous PAN types,

granulomatous vasculitis, and lymphocytic vasculitis and finally occlusive

intravascular histiocytic foci for which the designation of 'RA-associated

intravascular histiocytopathy' is proposed. Rheumatoid factor (RF)

positivity and active arthritis were common in this group, with anti-Ro and

anticardiolipin antibodies being co-factors contributing to vascular injury

in some cases. Immunofluorescent testing in three patients revealed dominant

vascular IgA deposition. In nine patients, the main pattern was one of

neutrophilic dermal and/or subcuticular infiltrates manifested clinically as

urticarial plaques, pyoderma gangrenosum and panniculitis.

CONCLUSIONS: The cutaneous manifestations of RA are varied and encompass a

number of entities, some of which define the dominant clinical features,

such as the rheumatoid papule or subcutaneous cords, while others allude to

the histopathology, i.e. rheumatoid neutrophilic dermatosis. We propose a

more simplified classification scheme using the adjectival modifiers of

'rheumatoid-associated' and then further categorizing the lesion according

to the dominant reaction pattern. Three principal reaction patterns are

recognized, namely extravascular palisading granulomatous inflammation,

interstitial and/or subcuticular neutrophilia and active vasculopathy

encompassing lymphocyte-dominant, neutrophil-rich and granulomatous

vasculitis. In most cases, an overlap of the three reaction patterns is

seen. Co-factors for the vascular injury that we believe are integral to the

skin lesions of RA include RF, anti-endothelial antibodies of IgA class,

anti-Ro and anticardiolipin antibodies.

http://www.thedoctorsdoctor.com/diseases/rheumatoidarthritis.htm

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Mayo Clinic in Rochester

http://www.mayoclinic.org/rochester

s Hopkins Medicine

http://www.hopkinsmedicine.org