Most people with multiple sclerosis -- around 85% -- have this type. They usually have their first signs of the disease in their early 20s. After that, they have attacks of symptoms (called relapses) from time to time, followed by weeks, months, or years of recovery (called remissions).
The nerves that are affected, how severe attacks are, the degree of recovery, and the time between relapses all vary widely from person to person.
Eventually, most people with relapsing-remitting MS will move on to a secondary progressive phase of MS.
Primary Progressive Multiple Sclerosis
In primary progressive multiple sclerosis, the disease gradually gets worse over time. There are no well-defined attacks of symptoms, and there is little or no recovery. In addition, MS treatments don't work as well with this type of MS. About 10% of people with MS have this type.
A few things make it different from other types of MS:
People with primary progressive MS are usually older when they’re diagnosed -- an average age of 40.
Roughly equal numbers of men and women get it. In other types of the disease, women outnumber men 3 to 1.
It usually leads to disability earlier than the most common type, relapsing-remitting MS.
Secondary Progressive Multiple Sclerosis
After living with relapsing-remitting MS for many years, most people will get secondary progressive MS. In this type, symptoms begin a steady march without relapses or remissions. (In this way, it’s like primary progressive MS.) The change typically happens between 10 and 20 years after you’re diagnosed with relapsing-remitting MS.
It's unclear why the disease makes the shift. But scientists know a few things about the process:
The older a person is when she’s first diagnosed, the shorter the time she has before the disease becomes secondary progressive.
People who don’t fully recover from relapses generally move to secondary progressive MS sooner than those who do.
The process of ongoing nerve damage changes. After the transformation, there's less inflammation and more of a slow decline in how well the nerves work.
Secondary progressive MS is tough to treat, and the disease can be hard to handle day to day. Symptoms get worse at a different rate for each person. Treatments work moderately well, but most people will have some trouble using their body like they used to.