A potassium hydroxide preparation (KOH) from skin scrapings from the scalp lesions demonstrated no fungal elements. Further laboratory work up revealed a normal blood cell count, normal liver enzymes, an antinuclear antibody (ANA) titer of less than 1:80, a positive anti–Sjögren’s syndrome type B (SSB) antibody but negative anti–Sjögren’s syndrome type A (SSA) antibody and anti-U1RNP antibody. An electrocardiogram revealed no abnormalities. Liver function tests were normal. The complete blood count showed mild thrombocytopenia. Given the typical skin lesions and the positive SSB test and associated thrombocytopenia, the baby was diagnosed with neonatal lupus erythematosus.
Dr. Catalina Matiz
Because of the diagnosis of neonatal lupus the mother was also tested and was found to have an elevated ANA of 1:640, positive SSB and antiphospholipid antibodies. The mother was healthy and her review of systems was negative for any collagen vascular disease–related symptoms.
Discussion
Neonatal lupus erythematosus (NLE) is a rare form of systemic lupus erythematosus (SLE) believed to be caused by transplacental transfer of anti-Ro (Sjögren’s syndrome antigen A, SSA), or, less commonly, anti-La (Sjögren’s syndrome antigen B, SSB) from mothers who are positive for these antibodies. Approximately 95% of NLE is associated with maternal anti-SSA; of these cases, 40% are also associated with maternal anti-SSB.1 Only about 2% of children of mothers who have anti-SSA or anti-SSB develop NLE, a finding that has led some researchers to postulate that maternal factors, fetal genetic factors, and environmental factors determine which children of anti-SSA or SSB positive mothers develop NLE.
A recent review found no association between the development of NLE and fetal birth weight, prematurity, or age.3 Over half of mothers of children who develop NLE are asymptomatic at the time of diagnosis of the neonate,3 though many become symptomatic in following years. Of mothers who are symptomatic, SLE and undifferentiated autoimmune syndrome are the most common diagnoses, though NLE has been rarely reported in the offspring of mothers with Sjögren’s syndrome, rheumatoid arthritis, and psoriasis.4,5
Fetal genetics are not an absolute determinant of development of NLE, as discordance in the development of NLE in twins has been reported. However, certain genetic relationships have been established. Fetal mutations in tumor necrosis factor–alpha appear to increase the likelihood of cutaneous manifestations. Mutations in transforming growth factor beta appear to increase the likelihood of cardiac manifestations, and experiments in cultured mouse cardiocytes have shown anti-SSB antibodies to impair macrophage phagocytosis of apoptotic cells in the developing fetal heart. These observations taken together suggest a fibroblast-mediated response to unphagocytosed cardiocyte debris may account for conduction abnormalities in neonates with NLE-induced heart block.6
Cutaneous disease in NLE is possible at birth, but more skin findings develop upon exposure to the sun. Nearly 80% of neonates affected by NLE develop cutaneous manifestations in the first few months of life. The head, neck, and extensor surfaces of the arms are most commonly affected, presumably because they are most likely to be exposed to the sun. Erythematous, annular, or discoid lesions are most common, and periorbital erythema with or without scale (“raccoon eyes”) should prompt consideration of NLE. However, annular, or discoid lesions are sometimes not present in NLE; telangiectasias, bullae, atrophic divots (“ice-pick scars”) or ulcerations may be seen instead. Lesions in the genital area have been described in fewer than 5% of patients with NLE.
The differential diagnosis of annular, scaly lesions in neonates includes annular erythema of infancy, tinea corporis, and seborrheic dermatitis. Annular erythema of infancy is a rare skin condition characterized by a cyclical eruption of erythematous annular lesions with minimal scaling which resolve spontaneously within a few weeks to months without leaving scaring or pigment changes. There is no treatment needed as the lesions self-resolve.7 Acute urticaria can sometimes appear similar to NLE but these are not scaly and also the lesions will disappear within 24-36 hours, compared with NLE lesions, which may take weeks to months to go away. Seborrheic dermatitis is a common skin condition seen in newborns with in the first few weeks of life and can present as scaly annular erythematous plaques on the face, scalp, torso, and the diaper area. Seborrheic dermatitis usually responds well to a combination of an antiyeast cream and a low-potency topical corticosteroid medication.
Ayan Kusari
When NLE is suspected, diagnostic testing for lupus antibodies (anti-SSA, anti-SSB, and anti-U1RNP) in both maternal and neonatal serum should be undertaken. The presence of a characteristic rash plus maternal or neonatal antibodies is sufficient to make the diagnosis. If the rash is less characteristic, a biopsy showing an interface dermatitis can help solidify the diagnosis. Neonates with cutaneous manifestations of lupus may also have systemic disease. The most common and serious complication is heart block, whose pathophysiology is described above. Neonates with evidence of first-, second-, or third-degree heart block should be referred to a pediatric cardiologist for careful monitoring and management. Hepatic involvement has been reported, but is usually mild. Hematologic abnormalities have also been described that include anemia, neutropenia, and thrombocytopenia, which resolve by 9 months of age. Central nervous system involvement may rarely occur. The mainstay of treatment for the rash in NLE is diligent sun avoidance and sun protection. Topical corticosteroids may be used, but are not needed as the rash typically resolves by 9 months to 1 year without treatment. Mothers who have one child with NLE should be advised that they are more likely to have another with NLE – the risk is as high as 30%-40% in the second child. Hydroxychloroquine taken during subsequent pregnancies can reduce the incidence of cardiac complications,8 as can the so-called “triple therapy” of plasmapheresis, steroids, and IVIg.9
The cutaneous manifestations of NLE are usually self-limiting. However, they can serve as important clues that can prompt diagnosis of SLE in the mother, investigation of cardiac complications in the infant, and appropriate preventative care in future pregnancies.
Dr. Matiz is with the department of dermatology, Southern California Permanente Medical Group, San Diego. Mr. Kusari is with the department of dermatology, University of California, San Francisco.
References
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