A case of cutaneous polyarteritis nodosa manifested by spiking high fever, arthralgia and macular eruption like adult-onset Still's disease.

A 24-year-old Japanese woman was admitted for investigation of recurrent spiking high fever associated with a macular eruption of the upper extremities associated with fever and polyarthralgia. These symptoms were self-limiting but recurrent and seemed to be consistent with a diagnosis of adult-onset Still's disease (AOSD). However, livedo reticularis was detected on the lower extremities, suggesting the presence of vasculitic disease rather than AOSD. Investigation did not reveal any evidence of visceral involvement. Skin biopsy of the affected lower extremity demonstrated a necrotizing vasculitis of small muscular artery and confirmed a diagnosis of cutaneous polyarteritis nodosa (PAN) rather than AOSD. Treatment with 30 mg of prednisolone daily improved the skin lesions and the recurrent spiking high fever and the arthralgia were resolved. PAN and AOSD are clinically similar, and discrimination may be sometimes difficult. The presence of livedo reticularis and the finding of a characteristic skin biopsy appearance may be diagnostically useful to distinguish PAN from AOSD. Indeed, the clinical features of cutaneous PAN may be more similar to AOSD than systemic PAN, and a skin biopsy may be necessary to distinguish cutaneous PAN from AOSD in some cases.