Infant unbothered by all-over body rash?

Case: This rash has developed over the past few months in a 4-month-old girl. The infant does not seem to be bothered by it. Her mother thinks that the rash started a few days after a family picnic. Do you recognize this rash? (Answer on next page.) Answer Case: This infant has neonatal lupus erythematosus (NLE)--a disorder caused by the transplacental trans-fer of maternal antibodies to a genetically susceptible child. NLE is usually precipitated by an environmental agent (eg, ultraviolet light). This cutaneous eruption develops in children younger than 6 months; it resolves by the time they are 6 or 7 months old. Unfortunately, NLE is associated with congenital heart block in approximately 10% of affected children. The cutaneous findings are usually similar to those of subacute cutaneous lupus, with erythematous and edematous plaques in sun-exposed areas that have an annular, polycyclic morphology. Many of these lesions have an overlying scale, but the "carpet tack" scale of discoid lupus is not present. Periorbital involvement is common enough to warrant the clinical term "raccoon eyes." The most significant event associated with NLE is heart block, which is complete in 90% of cases and is associated with 15% to 20% mortality. Autopsy findings show the replacement of the conducting system with connective tissue. Mothers of infants with NLE have anti-Ro/SS-A autoantibodies in 95% of cases. Surprisingly, affected mothers are almost always asymptomatic and are unaware of their antibody status. Unfortunately, systemic lupus erythematous or Sjögren syndrome will develop at some point in approximately 60% of these women. Mothers who are anti-Ro/SS-A-positive have a 7% chance of bearing a child with NLE. The risk rises to about 20% during a second pregnancy. Topical corticosteroids and sunscreen protection effectively treat the transient cutaneous lesions of NLE. The steroids can cause scarring, however; thus, the potency of the agent you choose should be sufficient to eradicate the inflammatory cutaneous process. If heart block is discovered, there is evidence that therapy should be directed toward reducing the inflammatory reaction in addition to specific cardiac therapy. There are now a number of adolescents who had NLE as infants and in whom SLE subsequently developed. This supports the hypothesis that this condition is the result of transplacental transfer of antibody to a genetically susceptible person.