Neonatal lupus is a condition that may cause a rash and, in some cases, congenital heart blockage. It can range in severity from a mild rash to a life threatening heart blockage.

Neonatal lupus occurs as a reaction to autoimmune antibodies passing onto the fetus, causing a rash or, in severe cases, a heart blockage.

This article explores neonatal lupus, its symptoms, causes, treatments, and more.

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Despite its name, neonatal lupus is not the infant version of lupus. The term originates from its characteristic rash that resembles lupus.

Neonatal lupus, also known as neonatal lupus erythematosus, congenital heart block, or neonatal lupus syndrome, is a rare, acquired autoimmune disorder that a pregnant individual passes down to a fetus.

It occurs when autoantigen type A (Ro/SSA) or B (La/SSB), antibodies relating to Sjögren’s disease, pass to the developing fetus. It affects about 2% of all babies born to people with autoantibodies of Sjögren’s disease, with an 18–20% chance of it occurring again in subsequent pregnancies.

Learn about Sjögren’s disease.

The most common symptom is a ring-like rash that appears within the first few weeks of life and typically clears within a few months. The rash typically appears within 6 weeks after birth.

The most serious complication is the potential for congenital heart block. However, doctors do not know if the occurrence of a heart block is as common as the rash.

The severity of the block can range from first- to third-degree block, with the third-degree block being the most severe. Complete heart block is permanent and may be life threatening.

Some infants may have additional symptoms such as atypical blood counts and liver issues. However, these should clear within about 6 months.

In rare cases, a person may have an atypically large head, known as macrocephaly. In some of these cases, a baby may have an atypical amount of spinal fluid in the brain cavity, putting pressure on the tissue of the brain.

Congenital heart block is the most dangerous complication of neonatal lupus. It causes interference with the transfer of the heartbeat from the top to the middle of the heart. The middle portion, or the conduction system, controls the rate of the heartbeats.

A person may have first-, second-, or third-degree congenital heart block.

  • First-degree block: In first-degree heart block, a slight lag occurs between the top and bottom chambers of the heart. However, this typically does not cause any clinical concerns.
  • Second-degree block: Moderate cases of heart block cause only some of the beats to transfer from the upper to lower chambers, which slows the heart rate down.
  • Third-degree block: Third-degree heart block is the most severe form and occurs when no beats transfer from the upper to the lower chambers. This can lead to symptoms, including blackouts, breathlessness, or irregular heartbeats. A person may also develop heart muscle disease, and their heart walls may become thickened. Heart failure or sudden cardiac arrest can also occur in severe cases.

Learn more about heart block.

Neonatal lupus is an acquired condition that a pregnant individual passes on to a developing fetus. It occurs due to a natural process that accidentally introduces autoantibodies to a developing fetus.

During pregnancy, the pregnant person passes several substances to the fetus to help its development, including antibodies. Antibodies make up part of the body’s natural defense system, the immune system. They play a vital role in helping fight bacteria, viruses, and other antigens a person comes into contact with.

In cases of neonatal lupus, a pregnant individual’s autoantibodies transfer to the fetus during development. Autoantibodies develop in the pregnant person due to an autoimmune disorder, such as Sjögren’s disease, rheumatoid arthritis, or lupus, and these autoantibodies attack and damage healthy cells.

The most common antibodies relating to neonatal lupus include anti-Ro/SSA antibodies, the anti-La/SSB antibodies, or both.

A pregnant person does not need to have clinical signs of any of the associated disorders, and many do not. All they need is the presence of the antibodies to pass it down to their unborn child.

Researchers state that the risk of heart block in an infant of a pregnant person with these autoantibodies and no previous children with heart block appears to be around 2%.

Due to the relatively low incident rate, experts suspect other genetic factors and environmental causes play a role in the development of the condition.

Several conditions can present with a rash at or shortly after birth. Some of them may be more common than neonatal lupus, but a doctor will need to rule out other possible causes, including:

Often these conditions and infections have additional features that distinguish them from neonatal lupus and each other.

Diagnosis can potentially start before birth. When doctors examine a fetus, they typically check the heart rate. If they find abnormalities, they will often order an echocardiogram to generate an image of the heart, which can help diagnose potential blocks.

If they suspect neonatal lupus, they will likely order a blood test to check for anti-Ro and La antibodies.

A doctor may be able to diagnose the rash according to its appearance and will likely not need a new blood test, as the pregnant person’s blood test will show the presence of the antibodies.

Treatment will vary according to the severity of the condition and the resulting symptoms.

When a rash appears, it should clear on its own, with no need for treatment. If a person requires treatment, doctors often recommend topical steroids. However, parents and caregivers should take precautions in the sun and cover the baby’s skin with protective clothing or apply sunscreen.

Doctors will likely perform a full examination to determine whether there are blood or liver problems to address. Treatments will vary according to whether the tests are positive for these complications.

Infants with severe heart blockage will likely need a pacemaker. Those with less severe forms may require regular monitoring to ensure they stay healthy.

Some studies suggest a parent can take steps to prevent subsequent children from developing the condition. According to a 2020 study, researchers found that hydroxychloroquine, an antimalarial medication, can help prevent subsequent babies from developing the complication.

Several organizations may be able to provide support services, additional resources, community involvement, and more for people who look after an infant with neonatal lupus.

Lupus and Allied Diseases Association,
Lupus Foundation of

The outlook for neonatal lupus will depend on the presence and severity of a heart blockage.

Infants who only experience the rash will often see their symptoms resolve without treatment.

However, those with a heart block will likely need regular monitoring or a pacemaker.

In rare cases, the condition can cause heart failure or cardiac arrest.

Neonatal lupus is a rare congenital disorder that most often causes a rash and, in some cases, heart blockage. It often has links to autoimmune antibodies entering the fetus during pregnancy.

The rash will often clear on its own, but heart blockages may require a pacemaker or regular monitoring.

Several conditions present at or near birth have similar symptoms. Many are more common than neonatal lupus, and a doctor will likely look to rule them out.

In some cases, diagnosis can start before birth. Monitoring the fetal heart rate and testing for antibodies in the pregnant person can help doctors diagnose the condition before the baby is born.