How Multiple Sclerosis Changes Over Time

Medically Reviewed by Christopher Melinosky, MD on October 26, 2023
3 min read

Multiple sclerosis (MS) is different for everyone who has it. The symptoms it causes and when they flare up vary not only between people but also throughout one person’s life. This means it can be hard for doctors to diagnose someone with the condition. They might say you "probably" or "possibly" have MS.

Your diagnosis is based on the symptoms you have, how and when they flare up or improve, which of your body’s functions give you trouble, and your test results. There’s no way to predict how your condition will change throughout your life. It may take time, but as your doctor gets more clues about the type of MS you have, you can have a clearer idea of how it will affect you in the coming years.

The way the disease changes and gets worse is different for each of the three types of MS:

  • Relapsing-remitting MS: People with this type have attacks when their symptoms get worse, called relapses, followed by full, partial, or no recovery. These flares seem to change over several days to weeks. Recovery from an attack takes weeks, sometimes months, but symptoms don’t get worse during this time. Most people have this type when they’re first diagnosed with MS.
  • Secondary-progressive MS: People who get this type usually start with relapsing-remitting MS. Over time, symptoms stop coming and going and begin getting steadily worse. The change may happen shortly after MS symptoms appear, or it may take years or decades.
  • Primary-progressive MS: In this type, symptoms gradually get worse without any obvious relapses or remissions. About 15% of all people with MS have this form, but it’s the most common type for people diagnosed after age 40.

An MS relapse starts when nerves in the brain and spinal cord get inflamed (swollen or irritated). Then, those nerves lose the coating, called myelin, that surrounds and protects them. A plaque forms around them instead.

A plaque in the brain or spinal cord changes the electrical signals that zip up and down nerves. They can get slower, distorted, or stop altogether. Those signal changes cause the symptoms of MS. One example of an MS flare is optic neuritis, inflammation of the nerve that connects the eye and the brain, which makes it harder to see.

Flares can be mild and not cause major problems, or they can severely affect your day-to-day life. They usually last from a few days to several weeks, though some can stick around for months.

Medications called corticosteroids can treat MS relapses. These drugs reduce inflammation. If you take them for a short amount of time, they can make the flare shorter and less severe.

Sometimes a symptom flare has nothing to do with the course of your disease, but happens because something has aggravated your condition, like a fever, infection, or hot weather. It’s called a pseudo-relapse or a pseudoexacerbation. For example, some people’s symptoms get worse during or after times of intense stress.

This break doesn’t mean that all the symptoms of MS disappear. Instead, you mostly return to the way you were before the last relapse began.