Causes
Mononeuritis multiplex: causes, symptoms and treatment
Mononeuritis multiplex means damage to two or more separate nerves, often one after another and on different sides of the body. It is a pattern rather than a single disease. Inflammation of the blood vessels that feed the nerves, called vasculitis, is a common cause, and diabetes is another. Because some causes damage nerves quickly, it needs prompt medical assessment.
Written by the Managing Neuropathy editorial team under the direction of Dr. Tom Biernacki, DPM, FACFAS · Clinical review pending · Last updated 5 October 2026
The short answer. Mononeuritis multiplex, also called multiple mononeuropathy, is damage to at least two separate nerves. It typically causes pain, numbness, tingling or weakness in the area each damaged nerve serves, such as a foot drop on one side and a weak, numb hand on the other, rather than the even, both-feet pattern of ordinary peripheral neuropathy. Common causes are vasculitis, connective tissue diseases such as rheumatoid arthritis and lupus, and diabetes; other causes include an inherited tendency to pressure palsies, infections, sarcoidosis and amyloidosis. Nerve tests, blood tests and sometimes a nerve biopsy look for the cause, and treatment is aimed at it: vasculitis is treated with steroids and often other medicines that calm the immune system. Recovery is possible, especially when the cause is found early and the nerve damage is limited.
What mononeuritis multiplex is
Most peripheral neuropathy is “length-dependent”: it starts in the toes of both feet, where the longest nerves end, and can creep evenly upward. Mononeuritis multiplex is different. Individual named nerves are damaged, at the same time or one after another, in patches: the nerve that lifts the foot on one side, say, then a nerve in the hand on the other. Each new area often comes on over days or weeks, though some people worsen slowly over months. It also goes by mononeuropathy multiplex, multiple mononeuropathy and multifocal neuropathy.
Over time the damaged areas can overlap. In a review of vasculitic neuropathy limited to the nerves, a fifth of people had an even, both-sides pattern that looks like ordinary neuropathy, so the patchy start is an important clue to mention to your clinician.
Symptoms
Symptoms appear in the area each damaged nerve serves, and usually differ from side to side:
- Pain, which can be burning. In vasculitic neuropathy limited to the nerves, about 80 percent of people have pain.
- Numbness, tingling or burning in a patch of skin, such as the top of one foot or the little-finger side of one hand.
- Weakness or paralysis of the muscles a nerve supplies. A foot drop, from damage to the peroneal nerve that lifts the foot, is a common sign: in vasculitic neuropathy, that nerve is affected in about 90 percent of people, and the ulnar nerve is the one most often hit in the arms.
- Loss of bladder or bowel control, which is rare.
When the vasculitis also affects other organs, weight loss, fever and feeling unwell are common. More on peroneal nerve damage and foot drop.
What causes it
Anything that cuts off the blood supply to several nerves, or inflames or presses on them, can cause it. MedlinePlus lists the common causes as:
- Diseases of the blood vessels, such as polyarteritis nodosa and other forms of vasculitis.
- Connective tissue diseases, such as rheumatoid arthritis and lupus.
- Diabetes.
- An inherited tendency for nerves to be injured by pressure, such as hereditary neuropathy with liability to pressure palsies (HNPP).
Less common causes include amyloidosis, blood disorders, granulomatosis with polyangiitis, infections such as Lyme disease, HIV and hepatitis, leprosy, sarcoidosis and Sjögren syndrome.
Nerve damage from vasculitis is common in some of these diseases. Reported rates of vasculitic neuropathy, from a 2024 review in Practical Neurology:
| Condition | People with vasculitic nerve damage |
|---|---|
| Polyarteritis nodosa | 65 to 85 percent |
| Eosinophilic granulomatosis with polyangiitis | 60 to 80 percent |
| Microscopic polyangiitis | 40 to 50 percent |
| Cryoglobulinemic vasculitis | 30 to 70 percent |
Vasculitic nerve damage also occurs in Sjögren disease, lupus and rheumatoid arthritis, but far less often than in the conditions above.
In some people the vasculitis affects only the nerves, with no other organ involved. This is called nonsystemic vasculitic neuropathy, and it accounts for about 28 percent of vasculitic neuropathy.
How it’s diagnosed
An examination maps which nerves are affected. Tests then confirm the pattern and look for the cause:
- A nerve conduction study and EMG show damage in several separate nerves, often in an uneven, patchy pattern, and can find damage that hasn’t caused symptoms yet.
- Blood tests look for inflammation and autoimmune disease, for example the sedimentation rate, C-reactive protein, an antinuclear antibody panel and rheumatoid factor, along with blood chemistry and thyroid tests.
- Imaging, such as X-rays, and sometimes genetic tests.
- A nerve biopsy: a small piece of an affected sensory nerve that runs just under the skin, usually in the lower leg or at the ankle and sometimes in the forearm, is examined for inflamed blood vessels. Taking a piece of muscle at the same time raises the chance of finding vasculitis by 5 to 25 percent.
The diagnosis is often slow: for vasculitic neuropathy limited to the nerves, reported median delays range from 2.5 to 24 months. If you have new patches of numbness or weakness in separate places, ask whether mononeuritis multiplex has been considered.
Treatment
Treatment targets the cause and protects the body while the nerves recover:
Steroids are usually the main treatment. When vasculitis also affects other organs, they are often combined from the start with another immune-suppressing medicine, such as cyclophosphamide or rituximab. When it affects only the nerves, steroids alone often come first, and cyclophosphamide, methotrexate or azathioprine is added, usually for 18 to 24 months, if the disease is aggressive or getting worse. This combination has been linked with fewer relapses than steroids alone.
Managing blood sugar in diabetes, treating an infection, and avoiding pressure on vulnerable nerves in HNPP.
Physical and occupational therapy, and an ankle-foot brace for a foot drop.
Medicines used for nerve pain, such as amitriptyline, duloxetine, gabapentin or pregabalin. How nerve pain medicines compare.
Check numb skin for injuries you can’t feel, and make the home safe against falls.
Outlook
MedlinePlus says a full recovery is possible if the cause is found and treated and the nerve damage is limited. For vasculitic neuropathy limited to the nerves, the 2024 review reports that up to 82 percent of people on immune-suppressing treatment regain or keep the ability to walk without aids, and only 3 percent lose it. Pain is harder: in vasculitic neuropathy generally, 44 to 71 percent of people who otherwise respond well to treatment have chronic pain. Younger people tend to do better.
When to get help urgently
- Get seen the same day for a new foot drop or hand weakness (call 911 instead if it came on suddenly), or numbness or weakness that is spreading to new areas over days, especially with fever, weight loss or a new rash, or if you already have vasculitis, rheumatoid arthritis or lupus.
- Go to an emergency department for numbness around the genitals or bottom, new bladder or bowel trouble, or weakness or numbness in both legs that is severe or getting worse.
- Call 911 for sudden numbness or weakness of the face, an arm or a leg, especially on one side, or sudden trouble speaking: possible stroke.
- See a clinician soon for a patch of numbness or tingling that doesn’t settle, even if it is your only symptom.
Common questions
Is mononeuritis multiplex serious?
It can be. It is often a sign of vasculitis or another illness that needs treatment, and the nerve damage can build up if the cause isn’t found. With prompt treatment many people do well: in vasculitic neuropathy limited to the nerves, up to 82 percent of people on treatment regain or keep the ability to walk without aids.
What is the most common cause of mononeuritis multiplex?
Vasculitis, inflammation of the blood vessels that supply the nerves, is a leading cause, whether it is part of a disease such as polyarteritis nodosa, rheumatoid arthritis or lupus, or limited to the nerves. Diabetes is another common cause. It can also come from infections, sarcoidosis, amyloidosis or an inherited tendency to pressure palsies.
Can mononeuritis multiplex be reversed?
Often, at least partly. MedlinePlus says a full recovery is possible if the cause is found and treated and the nerve damage is limited. Nerves regrow slowly, so recovery can take months, and some pain or numbness can remain.
How is mononeuritis multiplex different from peripheral neuropathy?
Ordinary peripheral neuropathy usually starts evenly in both feet and spreads upward. Mononeuritis multiplex damages individual nerves in separate places, often over days or weeks and on different sides, such as a foot drop on one side and a numb hand on the other. Over time the patches can merge and look more even.
What tests diagnose mononeuritis multiplex?
A nerve conduction study and EMG show the patchy pattern of nerve damage. Blood tests look for inflammation, autoimmune disease and other causes, and a nerve biopsy, often with a muscle biopsy, can confirm vasculitis.
Related reading
Types of neuropathy · Peroneal neuropathy · Foot drop exercises · Nerve conduction study and EMG · Diabetic neuropathy · Neuropathic pain
Sources and further reading: MedlinePlus, Multiple mononeuropathy, reviewed 2026. American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM), Mononeuritis multiplex. Diagnosis and treatment of vasculitic neuropathy, Practical Neurology (US), April 2024, for how often vasculitis damages nerves in each disease, the nerves affected, pain, delays in diagnosis, nerve and muscle biopsy, treatment and outcomes. Hellmich B et al., EULAR recommendations for the management of ANCA-associated vasculitis: 2022 update, Annals of the Rheumatic Diseases, 2024. Johns Hopkins Vasculitis Center, Rheumatoid vasculitis. NICE, Neuropathic pain in adults: pharmacological management in non-specialist settings (CG173). NINDS, peripheral neuropathy, on length-dependent neuropathy. Warning signs: NHS, sciatica, on symptoms that need emergency care; CDC, stroke signs and symptoms.
This page is general education and is not a diagnosis, a treatment plan, or a substitute for care from your own clinician. Clinical review by Dr. Biernacki is pending; the review date will be shown here once complete.
For our Michigan neighbors
A foot drop,
or numb patches on your feet?
Mononeuritis multiplex is usually managed by a neurologist, often with a rheumatologist when vasculitis is the cause. A foot drop or numbness in the feet also deserves a foot examination and the right brace or footwear. Dr. Biernacki’s Michigan practice can help with that part.
Everywhere else, take this page to your own clinician.
Dr. Tom Biernacki, DPM, FACFAS is a double board-certified foot and ankle surgeon (ABFAS and ABPM) and a Fellow of the American College of Foot & Ankle Surgeons. He is the founder of Balance Foot & Ankle in Howell and Bloomfield Township, Michigan, where peripheral neuropathy, diabetic foot risk and loss of protective sensation are part of his weekly clinic. His patient education videos have drawn more than 950,000 subscribers on YouTube. Managing Neuropathy is written by its editorial team under his direction, to put the explanation he gives in the exam room in front of the people who cannot get to one — including when a product is worth buying and when it is not.