Lupus Erythematosus and Neutrophilic Urticarial Dermatosis: A Retrospective Study of 7 Patients

Neutrophilic urticarial dermatosis (NUD) resembles urticaria clinically but is a neutrophilic dermatosis histopathologically. The majority of patients with NUD have an underlying systemic condition, mainly, autoinflammatory disorders such as cryopyrin-associated periodic syndromes, Schnitzler syndrome, and adult-onset Still disease, but a few also have systemic lupus erythematosus (LE). Here, we confirm these data and we report relevant clinical and histopathological data of 7 patients with LE and NUD. We retrospectively retrieved the medical records of all patients with LE in whom skin biopsy showed NUD in registers of Strasbourg and Montpellier University hospitals since 2000. All were female and aged between 13 and 45 years. Skin lesions were typically rose or red macules or slightly elevated papules occurring in a wide distribution. Individual lesions resolved within 24 hours and were not or only slightly itchy. Every patient had associated signs, most of the time polyarthritis and/or fever. NUD was the presenting mode of LE in 2 patients. NUD was misdiagnosed as a classic lupus flare and led to therapeutic intensification with the introduction of immunosuppressive drugs in 4 patients. Histopathological findings consisted of intense neutrophilic interstitial and perivascular infiltrate with leukocytoclasia and without fibrinoid necrosis of vessel walls. Direct immunofluorescence testing showed a lupus band in 4 patients. Antinuclear antibodies were always positive, anti-dsDNA antibodies were positive in 5 patients, and anti-Ro/SSA antibodies in 6 patients. Immunosuppressive drugs such as prednisone, hydroxychloroquine, mycophenolate mofetil, and methotrexate were never effective to treat NUD. Antihistamines were effective in 1 patient and dapsone or colchicine was effective in 5 patients. NUD is not exceptional in patients with systemic LE and is easily misdiagnosed as an acute LE flare. Furthermore, we show that conventional immunosuppressive LE treatments are not efficient and we underline the major interest of dapsone and colchicine, classic neutrophil migration inhibitors, in those patients.