[Neonatal lupus erythematosus, a clinical case]

Neonatal lupus erythematosus (NLE) is a very rare autoimmune disease, occurring in neonates born to mothers who present auto-antibodies to cytoplasmic antigens of Sjögren's syndrome. In most cases, the clinical course is benign toward spontaneous resolution, but there is a group of patients who develop severe involvement of the cardiac conduction system, therefore, early detection is critical.

To describe a clinical case of neonatal lupus erythematosus emphasizing the importance of timely diagnosis in the patient and the mother.

A 33-year-old woman, with a history of hypertension, came to the dermatology department for her 15-day-old male neonate who presented a recent onset of round, erythematous, raised-edged, and non-scaling plaques consistent with NLE. Cardiac conduction involvement was ruled out. Newborn's laboratory tests showed moderate neutropenia, mild increase of transaminases, and positive anti-Ro and anti-La antibodies. On directed anamnesis, the mother reported a personal history of symptoms consistent with connective tissue disease, such as fatigue, alopecia, and xerophthalmia. Antinuclear antibodies from the mother showed titers of 1/1280 in a speckled pattern, positive anti-double-stranded DNA antibodies, and anti-Ro and Anti-La antibodies. Schirmer Test was consistent with dry eye, therefore, Systemic Lupus Erythematosus associated with Sjögren's Syndrome was diagnosed. The infant was followed up for 5 months with remission of cutaneous manifestations and normalization of laboratory tests.

Although cutaneous manifestations of NLE are benign and transient in the newborn, these can be associated with other life-threatening manifestations that require an active search and prompt management by the medical team. A 25% of mothers of newborns with NLE are asymptomatic or unaware of their SLE diagnosis before delivery, so timely diagnosis of NLE leads to the diagnosis of asymptomatic mothers, improving their follow-up and treatment.