Susac Syndrome

Susac syndrome is an autoimmune condition where your immune system attacks the smallest blood vessels in your brain, retina (part of the eye) and inner ear. Symptoms affect these areas but not all at the same time. You may have symptoms only once in your life, several times or have continuous flare-ups.


What is Susac syndrome?

Susac syndrome is an autoimmune condition where your immune system mistakenly attacks small blood vessels in your brain, eyes (retina) and inner ear (cochlea). This attack blocks or decreases blood flow and causes symptoms like hearing and vision loss.

What parts of the body can Susac syndrome affect?

Susac syndrome classically involves the following three areas of the body and associated symptoms:

  • Brain: A problem with brain function (encephalopathy) that causes headaches and confusion.
  • Eyes: Losing areas of your vision.
  • Ears: Hearing loss can be subtle or dramatic.

How common is Susac syndrome?

Susac syndrome is rare. The exact rate of occurrence is unknown. Studies estimate that the number of people diagnosed with the condition is lower than expected due to a misdiagnosis of Susac syndrome as a form of multiple sclerosis (MS).


Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

Symptoms and Causes

What are the symptoms of Susac syndrome?

Symptoms vary from person to person but affect your brain, eyes and ears.

Brain symptoms may include:

  • Severe headache.
  • Problems with thinking, such as short-term memory loss, slow thought processing and reduced ability to solve problems.
  • Slurred speech.
  • Trouble walking.
  • Personality changes.
  • Psychological problems such as depression, psychosis, aggression or anxiety.

Eye symptoms may include:

  • A dark area in part(s) of your visual field.
  • A visual disturbance described as “a dark shade or curtain” covering part of your vision.
  • Loss of peripheral (side) vision.

Inner ear (cochlea) symptoms may include:

How will symptoms of Susac syndrome affect me?

Symptoms of Susac syndrome can be different from one person to the next. Some people have symptoms only once in their life. Others have symptoms that appear and disappear several times before going away completely. In most cases, symptoms come and go over a few years. Some people have long-term, continuous flare-ups of symptoms.

A small percentage of people diagnosed with Susac syndrome experience symptoms from all three areas of their body (brain, ears and eyes) at the time of diagnosis.

Your symptoms may flare up unexpectedly. This is most common if something interferes with your treatment, like you stop taking your medication as directed.

What causes Susac syndrome?

The exact cause of Susac syndrome is unknown.

Susac syndrome is an autoimmune condition. Your immune system protects your body from harmful things like bacteria to keep you healthy. When you have an autoimmune condition, your immune system mistakes healthy parts of your body for something harmful. Specifically in Susac syndrome, your immune system attacks the cells that line the inner walls of the blood vessels in your brain, retina and inner ear. When attacked, the cells swell and can partially or completely shut off blood flow through the vessel. The blockage prevents needed nutrients and oxygen from reaching these areas of your body.

Is Susac syndrome inherited?

No, there’s no evidence that Susac syndrome is an inherited condition (runs in families).

What are the risk factors for Susac syndrome?

Susac syndrome is three times more common among women or people assigned female at birth (AFAB) than it is for men or people assigned male at birth (AMAB). You’re most likely to start experiencing symptoms between the ages of 20 and 40.


What are the complications of Susac syndrome?

Damage to your eyes and ears caused by blood vessel blockages can permanently affect your vision and hearing. While rare, dementia is a possible complication, as well.

Diagnosis and Tests

How is Susac syndrome diagnosed?

A healthcare provider will make a Susac syndrome diagnosis after:

Testing helps your healthcare provider learn more about your symptoms and could include:

  • A magnetic resonance imaging (MRI) test: During this imaging test, a healthcare provider looks for round, “snowball” lesions (white spots) in the corpus callosum (the bundle of nerves that connects the left and right sides of your brain). These lesions are a sign of Susac syndrome.
  • Fluorescein angiography: This imaging test looks at the blood vessels in your retina. The retina is a layer of eye tissue that sends visual information to your brain to help you see. This test looks for vessel blockages.
  • An audiogram: This is a hearing test to identify if you have hearing loss. A sign of Susac syndrome is difficulty hearing low-pitched sounds or trouble understanding speech.

Because its symptoms are similar to those of several other conditions, such as multiple sclerosis, stroke, encephalitis and many others, Susac syndrome may be difficult to diagnose.


Management and Treatment

How is Susac syndrome treated?

Treatment for Susac syndrome may include taking long-term medications that suppress your immune system (immunosuppressants), like:

These medications come in different forms:

  • Oral tablet or capsule: You can take the medication by mouth with a glass of water as directed.
  • Injection: A healthcare provider will poke a small needle into your skin to inject medication into your body.
  • Intravenous (IV): A healthcare provider will place a small needle into a vein in your arm. Liquid medication slowly enters your bloodstream.

Immunosuppressive medications slow down how often your immune system attacks healthy parts of your body. Over time, the immune attacks become less frequent. Your healthcare provider could adjust the dosage of the medications you take. If you stop taking your medication as directed, you may experience an attack or flare-up of symptoms.

Are there side effects of the treatment?

Each medication comes with different side effects. Talk to your healthcare provider before starting treatment to learn more about the side effects. If you experience any side effects, let your healthcare provider know.

When will I feel better after treatment?

Susac syndrome can rapidly improve; the faster it’s diagnosed and treated the better. Some people only experience one episode of Susac syndrome, others may experience recurrence over the years. Being on immunosuppressant therapy will drastically decrease the risk of flaring.


Can Susac syndrome be prevented?

There’s no known way to prevent Susac syndrome. You can reduce your risk of experiencing a flare-up of symptoms by following your healthcare provider’s treatment plan.

Outlook / Prognosis

What’s the outlook for Susac syndrome?

The outlook is good for people diagnosed with Susac syndrome who receive treatment at the first sign of symptoms. This prevents long-term, irreversible damage to your brain, eyes and ears. In rare cases, the condition can cause permanent complications like vision loss and hearing loss.

What is the life expectancy for Susac syndrome?

Very rare cases of Susac syndrome are life-threatening. The condition may affect your quality of life but it doesn’t directly affect your life expectancy.

Living With

When should I see a healthcare provider?

Visit a healthcare provider if you experience changes to your:

  • Vision.
  • Hearing.
  • Cognitive (brain) function, like thinking or remembering.
  • Mood or personality.
  • Quality of life.

A healthcare provider can diagnose the cause of your symptoms to help you feel better and prevent long-term complications.

What questions should I ask my healthcare provider?

  • Will my symptoms come back after they go away?
  • What type of treatment do you recommend?
  • How often should I take this medication and how do I take it?
  • Are there side effects of the medication?
  • Am I a candidate for hearing aids or a cochlear implant?

A note from Cleveland Clinic

Susac syndrome can affect your day-to-day life. Senses that you rely on, like your vision and hearing, aren’t as reliable as they used to be. You may also experience changes to how your brain works, which can affect your mood or personality. Some people find comfort in talking with a mental health professional after receiving a Susac syndrome diagnosis. Complications are possible, so it’s best to let your healthcare provider know about your symptoms right away. Prompt treatment prevents permanent damage.

Medically Reviewed

Last reviewed on 08/18/2023.

Learn more about our editorial process.

Appointments 216.444.2606