Interstitial granulomatous dermatitis: a misdiagnosed cutaneous form of systemic lupus erythematosus?

Interstitial granulomatous dermatitis (IGD) is a recently described, rare dermatological entity. The clinical features are diverse and the precise aetiology is unknown. We present a rare and atypical case of IGD in a patient with systemic lupus erythematosus (SLE). A 26-year-old woman had been diagnosed with SLE when she was 15 years old. The diagnosis was based on cutaneous, articular, pulmonary, haematological and immunological features. The patient presented with a cutaneous diffuse macular eruption on the limbs, appearing in a cockade (rosette) pattern with a violaceous centre and erythematous surround. The face and trunk were spared. The cutaneous histological features led us to consider a diagnosis of IGD. The lesions disappeared after 15 days of systemic steroid therapy. This case is a new clinical form of IGD with an atypical location and clinical presentation. IGD has usually been associated with drug-related adverse reactions and autoimmune diseases. Reports in the literature of IGD in patients with SLE are rare.