Interstitial Granulomatous Dermatitis as the Initial Manifestation of Granulomatosis with Polyangiitis.

Interstitial granulomatous dermatitis (IGD) is a rare dermatological disorder. It is most commonly associated with autoimmune disorders mainly lupus and rheumatoid arthritis. It has rarely been reported to present as a first manifestation of an underlying vasculitis. Here, we present a case of a 44-year-old woman who presented initially with a violaceous rash starting in her neck and trunk and extending to her limbs, but sparing the palms and soles. She was also found to have an acute kidney injury. A biopsy of the skin lesion confirmed the diagnosis of IGD, and a kidney biopsy showed findings consistent with granulomatosis with polyangiitis. To the best of our knowledge, this is the seventh reported case of IGD associated with systemic vasculitis.