Arthritis with an inflammatory dermatosis resembling Sweet's syndrome. Report of a unique case and review of the literature on arthritis associated with the inflammatory dermatoses.

A patient with a unique case of chronic episodic arthritis coincident with flares of acneform, pustular, nodular and ulcerating skin lesions was observed over a five-year period. This patient and a review of the literature on arthritis associated with the inflammatory dermatoses provide evidence which may interrelate several of these nosologically confusing skin conditions, e.g., the family of leukocytoclastic angiitides with the newly posited acute febrile neutrophilic dermatosis of Sweet. Systemic manifestations and a variety of acneform, pustular, nodular and ulcerating cutaneous lesions in the inflammatory dermatoses are best explained by small vessel involvement, with individual syndromes being determined by the type and degree of vascular change. Perivascular neutrophilic infiltration is the unifying histologic feature of these small vessel diseases. Neutrophil infiltration differentiates these entities, and our patient, from the histologically nonspecific inflammations of the skin, e.g., Behcet's disease and pyoderma gangrenosum, which, although capable of causing identically appearing skin lesions, consist predominantly of lymphocytic dermal infiltrates even in the earlier stages. It appears important to recognized these morphologically varied acute inflammatory dermatoses with perivascular neutrophilic infiltration in view of their systemic features and the dramatic efficacy of corticosteroid therapy.