The onset of multiple sclerosis (MS) generally happens when people are between the ages of 20 to 40 years. It can, however, develop in people outside of this age range.

Early-onset MS starts in childhood. Late-onset MS, on the other hand, can begin after the age of 50 years. The symptoms of these two conditions generally do not differ much, but they can range in severity.

The exact cause of MS is not clear. However, experts believe it to be an autoimmune condition in which the body’s immune system attacks its tissues.

This article discusses when initial MS symptoms generally appear, and the typical age at which people receive a diagnosis. It also looks at the symptoms, types of diagnoses, and treatment.

A medical profesdional sat at a desk, looking at a screen showing a nerve diagramShare on Pinterest
Reza Estakhrian/Getty Images

The age of onset of MS for most people ranges from 20–40 years. Some people may receive a diagnosis at the onset. Others, however, may not get a diagnosis until years later. There is no cure for MS, meaning it is a lifelong condition.

The condition may start to develop after 50 years of age, in which case, doctors will refer to it as late-onset MS. Late-onset MS accounts for about 5% of people with MS. The symptoms are similar to those that occur in younger adults, but the condition’s progression is faster.

MS can also start in a person’s childhood and teen years. Doctors call this early-onset MS. Symptoms do not differ significantly from adult-onset MS, but research shows seizures are generally more common.

MS has an unpredictable course involving various symptoms, relapses, and remissions. The majority of people with MS have mild symptoms. However, some individuals experience difficulty with some actions, such as walking, speaking, and writing. Common symptoms of MS include:

Learn more about the symptoms of MS here.

There are multiple different subtypes of MS that may have different symptoms.

Clinically isolated syndrome (CIS)

CIS is a single episode of symptoms that may suggest that a person has MS. Experts believe it occurs due to an inflammatory condition of the brain or spinal cord. CIS symptoms last at least 24 hours. Some people with CIS will go on to develop MS while others may not.

There may only be a single symptom, such as vision loss, or multiple symptoms, such as vision loss alongside tingling or numbness in the legs.

When a person has CIS, a doctor will order an MRI scan to determine whether they have brain lesions similar to MS.

Brain lesions

In general, the presence of MRI-detected brain lesions means that a person may have a 60–80% risk of developing MS within several years. However, the absence of lesions suggests a 20–30% likelihood of developing MS within the same time frame.

Relapsing-remitting multiple sclerosis (RRMS)

About 85% of people with MS have the subtype called RRMS. It involves episodes of attacks that develop over a few days and last at least 24 hours but not more than 1–2 months. Between attacks, symptoms may either decrease or disappear.

Most individuals who have RRMS receive a diagnosis when they are in their 20s or 30s. Aside from numbness, tiredness, and stiffness, the most common RRMS symptoms a person may experience include problems with their vision, thinking, bowel, and bladder.

Primary progressive multiple sclerosis (PPMS)

About 15% of people with MS have a subtype called PPMS. Instead of relapses and remissions, individuals with PPMS experience a disability that progresses from the onset. However, PPMS can involve brief periods when the condition is stable.

People typically experience the onset of PPMS 10 years later than people with RRMS. Individuals with this subtype often experience more challenges with walking and remaining in the workforce. They may also need help performing everyday activities.

Secondary progressive multiple sclerosis (SPMS)

People who live with SPMS experience a gradual worsening of symptoms as time goes by. Relapses usually disappear as the condition progresses. Individuals with SPMS experience nerve loss or damage that becomes steadily more severe.

Before using disease-modifying therapies, about half of those with an RRMS diagnosis might transition to SPMS within 10 years, while almost all would transition to SPMS within 25 years.

However, the effect of disease-modifying treatments on altering or delaying the SPMS transition is unclear.

Research shows that MS affects many people, but there are certain populations in which MS is more common. According to the National Multiple Sclerosis Society (NMSS):

  • MS is three times more common in females than in males.
  • The condition is more common in states that are further away from the equator.
  • Although MS occurs in people of most ancestries, it is more common in people of northern European descent.

In terms of specific risk factors for MS, the NMSS lists several, including:

Diagnosing MS can be difficult and time consuming because there is no single test that can identify it. In addition, MS symptoms fluctuate and vary, making an accurate diagnosis challenging to obtain.

There is, however, an accepted diagnosis of MS called the 2017 McDonald Criteria. To diagnose the condition, doctors will look at a person’s:

Doctors assess the progression of MS (dissemination in time) and the parts of the body it affects (dissemination in space).

For dissemination in space, doctors will use imaging tests to look for two or more MS lesions, or one lesion and one clinical attack affecting the central nervous system.

For dissemination in time, they will look for:

  • at least two MS attacks that occurred at different times
  • MS lesions
  • new lesion development between MRI scans
  • the presence of oligoclonal bands in the cerebrospinal fluid

Learn more about the tests for an MS diagnosis here.

Many individuals with MS may be able to manage their condition without therapy.

However, a person may want to consider options that can help manage their MS and its symptoms to maintain their quality of life. These options may include:

  • rehabilitation
  • complimentary or alternative medication
  • relapse management

Several medications can help a person manage their MS.

Disease-modifying therapies

If a doctor decides that medication is necessary, they may prescribe disease-modifying therapies (DMTs). These drugs delay the progression of MS, reduce the frequency and severity of relapses, and limit new activity.

These DMTs may be injectable, oral, or intravenous infusions.

Injectable medications include:

  • Avonex (interferon beta-1a)
  • Betaseron (interferon beta-1b)
  • Extavia (interferon beta-1b)
  • Glatiramer Acetate Injection (glatiramer acetate)
  • Glatopa (glatiramer acetate)
  • Plegridy (peginterferon beta-1a)
  • Rebif (interferon beta-1a)
  • Kesimpta (ofatumumab)
  • Copaxone (glatiramer acetate)

Oral medications include:

  • Aubagio (teriflunomide)
  • Gilenya (fingolimod)
  • Ponvory (ponesimod)
  • Zeposia (ozanimod)
  • Bafiertam (monomethyl fumarate)
  • Dimethyl Fumarate (dimethyl fumarate)
  • Mavenclad (cladribine)
  • Mayzent (siponimod)
  • Tecfidera (dimethyl fumarate)
  • Vumerity (diroximel fumarate)

Infusion medications include:

  • Lemtrada (alemtuzumab)
  • Novantrone (mitoxantrone)
  • Ocrevus (ocrelizumab)
  • Tysabri (natalizumab)

Not all MS medications will be suitable for all patients. Doctors will work with a patient to create a tailored treatment plan specific to their condition. Some people with MS may require a doctor to administer high-efficacy drugs throughout the whole therapy course, while a gradual increase in drug strength may work better for others.

Learn more about the full range of DMTs and other MS treatment options here.

Symptom management

Doctors may prescribe other prescription and over-the-counter (OTC) medications to help treat specific MS symptoms.

  • Corticosteroids: These help reduce inflammation and may reduce flares.
  • Pain relievers: Muscle contractions and nerve damage can cause various pains. Prescription and OTC pain relievers can reduce general pain and improve a person’s daily quality of life.
  • Muscle relaxants: Muscle relaxants can treat and prevent muscle spasms that can occur in people with MS.
  • Antidepressants: People with MS may experience adverse mental health symptoms. Antidepressants and antianxiety medications, among others, can help manage these symptoms.

Generally, the onset of multiple sclerosis is between 20–40 years of age, but the condition may appear at an earlier or later age.

Most individuals have a subtype of MS that alternates between relapses and remissions, while a minority have a subtype that involves regular progression from the onset.

A person may be able to reduce their risk of developing MS by getting regular exposure to sunlight, maintaining a moderate weight, and stopping smoking. After diagnosis, there are various treatment options.