Allodynia

What is allodynia?

Allodynia is feeling pain from things that don’t usually cause pain. For example, a feather could touch your skin and it hurts instead of feeling soft. You might also feel pain from:

• Wearing clothing.
• Someone gently tapping your shoulder.
• Temperature changes.

Allodynia is a type of nerve pain (neuropathic pain). This is usually a symptom of conditions like diabetes, shingles, fibromyalgia and migraine headaches. To relieve allodynia, your provider will treat the condition that’s causing pain.

What does allodynia feel like?

Many people with allodynia describe their skin as sensitive. The sensation of touch can feel sharp, stinging or burning. Some might compare the pain to a bad sunburn.

What are the three types of allodynia?

There are three types of allodynia:

• Dynamic allodynia (mechanical): Pain results from an object moving across your skin (wearing clothing).
• Tactile allodynia (static or cutaneous allodynia): Pain results from a gentle touch or pressure on your skin (like shaking someone’s hand).
• Thermal allodynia: Pain results from a mild change in temperature (like moving from indoors to outdoors).

How common is allodynia?

Healthcare providers don’t know exactly how many people have allodynia. One study estimated that it affects 6.9% to 10% of people around the world.

What causes allodynia?

An error in pain processing within your nervous system causes allodynia. This is known as central sensitization, which is a structural, functional or chemical change to your central nervous system (CNS). This makes your CNS more sensitive to pain.

Think of central sensitization as a security system. You interact with the environment around you and your body learns from it. For example, if you touch a hot surface, your nerves will send a message to your security system. Your security system will set off an alarm alerting you of “danger.” This alarm tells your body to respond by moving your hand away from the heat source.

An underlying condition, injury or medication can interrupt how your central sensitization security system functions. When your security system isn’t getting the right messages, the alarm goes off at times when it usually wouldn’t, like if you touch something soft. This leads to symptoms of allodynia.

What conditions cause allodynia?

Many conditions can cause allodynia, including:

• Alcohol use disorder.
• Amplified musculoskeletal pain syndrome (AMPS).
• Complex regional pain syndrome (CRPS).
• Diabetes-related neuropathy.
• Fibromyalgia.
• Migraines.
• Multiple sclerosis (MS).
• Shingles (post-herpetic neuralgia).
• Trigeminal neuralgia (TN).
• Vitamin D or vitamin B deficiency.

You might experience allodynia after an injury. For example, a deep cut or an amputation can affect your nerve function. Trauma from a stroke can cause a heightened sensitivity to pain.

Certain types of treatment like radiation therapy or chemotherapy medications for cancer treatments can also lead to allodynia.

How will my provider determine the cause of allodynia?

Your provider will learn more about this symptom and your health history after a physical exam. They’ll ask you questions about your experience with pain, like what makes it feel better or worse. You’ll also rate the severity of your pain on a scale, usually from zero to 10, with 10 being the most painful. During your exam, tell your provider about any medications you’re taking.

Your provider may perform several tests to determine the cause. Some of these tests include:

• Blood tests (complete blood count).
• Urine tests.
• MRI (magnetic resonance imaging) or CT (computed tomography) scan.
• Electromyogram (EMG).
• Nerve conduction study (NCS).

How do you get rid of allodynia?

Your provider will treat allodynia by managing the underlying cause. If no treatments are available or your provider isn’t sure what’s causing it, they’ll focus on reducing pain. As part of a comprehensive pain management plan, your provider may recommend:

• Oral medications: Several types of medications can relieve allodynia, including (but not limited to) antiseizure medications and some antidepressants. Providers commonly prescribe pregabalin to treat fibromyalgia. Triptans (migraine medications) can relieve allodynia that happens with migraines. You take these medications orally (by mouth) as directed.
• Topical medications: Topical medications like capsaicin and lidocaine come in creams or lotions that you apply to your skin. You can also wear a patch on your skin that delivers medication throughout the day.
• Counseling and therapy: Living with chronic pain can be challenging and emotionally exhausting. Your provider may recommend counseling, especially if you have signs of depression. Counseling sessions may involve treatment methods like cognitive behavioral therapy (CBT) and biofeedback.
• Physical therapy (PT): Your provider may recommend a PT plan that focuses on desensitization. Your provider touches or puts gentle pressure on an area of your skin. Over several sessions, your provider gradually increases the pressure until it’s no longer painful.
• Injections: To reduce pain in a nerve or group of nerves, your provider may recommend a nerve block injection. A provider might recommend injections of botulinum toxin A to temporarily relieve pain, as well.
• Surgery: If other treatments aren’t successful, you may need surgery. Your provider may recommend spinal cord stimulation. For this treatment, your provider implants a device that delivers electricity directly to your spinal cord. Low levels of medical-grade electricity reduce pain instead of causing it.

How long does allodynia last?

How long this symptom lasts varies from person to person, depending on the cause. Sometimes, allodynia will go away on its own, especially if this symptom happens with migraines. It could take months to years for this symptom to go away. Treatment can address the underlying cause, which can reduce how long this symptom will affect you.

Does allodynia get worse?

Yes, allodynia can get worse over time. Treating the underlying cause can prevent this symptom from getting worse and causing more pain.

Can allodynia be prevented?

You may not be able to prevent allodynia. But you can lower your risk of some conditions that cause allodynia by:

• Participating in regular activities: Staying active with regular activities or exercise can help you manage stress. It also helps reduce your risk of migraine headaches. Exercise also plays a major role in fibromyalgia management.
• Knowing your history: If you have a family history of fibromyalgia, MS, stroke or diabetes, talk to your provider. You may need regular checkups so your provider can monitor your health.
• Maintaining a healthy weight: If you have obesity, you’re at a higher risk for diabetes, which can lead to allodynia. A healthcare provider can help you manage this.
• Staying up to date on vaccines: Ask your provider about getting the shingles vaccine to protect you from the viral infection.
• Eating well-balanced meals: Eating balanced meals rich in fruits and vegetables can help you avoid vitamin deficiencies.

When should allodynia be treated by a healthcare provider?

Call your healthcare provider if you have a strong sensitivity to touch or experience pain without a known cause. This is especially important if the pain gets in the way of your daily activities or makes it hard for you to sleep.

You should call your provider right away if allodynia comes on suddenly or is very painful. It’s important to see your provider for an evaluation and to determine what’s causing the pain.