Multiple Sclerosis (MS) is a chronic disease that affects the brain and spinal cord, leading to lifelong disability. It is an autoimmune condition wherein the immune system mistakenly attacks the protective myelin sheath that surrounds nerve fibres in the Central Nervous System (CNS) that most often affects individuals between the ages of 20 and 40, with women being more prone to developing the condition than men.

However, MS is said to be a slow disease, as its progression typically occurs over many years, sometimes decades. But exactly how long does it take for MS to be diagnosed? And can it remain undetected for years? Here's what an expert shared with us.

, said, "Multiple Sclerosis (MS) can remain undiagnosed for years. This is often due to the wide variety of symptoms that can mimic other neurological or autoimmune conditions. Early symptoms may be subtle, intermittent, or non-specific, such as fatigue, tingling, or mild vision problems, which patients may ignore or attribute to stress or lifestyle factors."

He added that inconsistent symptom patterns and lack of awareness among general physicians may result in misdiagnosis or delayed referrals to neurologists.

According to StatPearls Publishing, MS can develop at any age, but it most commonly begins between ages 20 and 40. The average age of onset is around 25–29 for the relapsing-remitting type and 39–41 for primary progressive MS. While it's less common in children, about 10% of cases appear before age 18. MS affects roughly 1 in 1,000 people of European ancestry.

MS can remain clinically silent for several months to even years before noticeable symptoms appear. “In some cases, early brain or spinal cord lesions may exist without causing any outward signs—a condition known as Radiologically Isolated Syndrome (RIS),” explained Dr Shukla. He added that only with time do symptoms like muscle weakness, numbness, balance issues, or vision problems become prominent enough to prompt further investigation.

Some of the earliest and often-overlooked signs of MS include:

According to Dr Shukla, these symptoms are frequently dismissed as minor or temporary, especially in younger adults. “Bladder urgency, unexplained clumsiness, or cognitive fog may also occur early but are often misattributed to other conditions like anxiety or migraines,” he shares.

Currently, there is no routine screening test that can detect MS before symptoms begin. However, Magnetic Resonance Imaging (MRI) scans sometimes incidentally reveal brain lesions suggestive of MS in asymptomatic individuals, as in RIS.

“While these lesions can raise suspicion, a diagnosis of MS is not confirmed until clinical symptoms appear or further tests (such as lumbar puncture or evoked potentials) show evidence of central nervous system inflammation,” said Dr Shukla.

Early intervention with Disease-Modifying Therapies (DMTs) has been shown to slow progression, reduce relapses, and delay disability, shared Dr Shukla, adding that when diagnosis is delayed, patients may already have developed significant lesions or accumulated disability, which can affect long-term outcomes and quality of life.

Hence, if someone strongly suspects MS based on recurring neurological symptoms even with normal initial test results, they should consult a neurologist specialising in MS. “It’s essential to document all symptoms, including their frequency, duration, and triggers. A second opinion, repeat MRI scans after a few months, or additional tests such as lumbar puncture may be necessary,” concluded Dr Shukla, adding that MS is a diagnosis that often unfolds over time, and persistence in follow-up is key when suspicion remains high.