Small Fiber Neuropathy Symptoms

The neuropathy of small fibers is a type of peripheral neuropathy. Peripheral neuropathies are conditions that influence the peripheral nervous system, which consists of the nerves that are located outside of the brain and the spinal cord. The small nerve fibers of the peripheral nervous system are affected by the condition known as small fiber neuropathy (SFN).

Small fiber neuropathy occurs when small myelinated (Aδ) nerve fibers and small unmyelinated C fibers are damaged. These fibers are involved in sensory functions that play a role in pain and temperature. They are also involved in involuntary processes in the body. Frequently, small fiber neuropathy occurs idiopathically (where the cause is unknown). However, patients with many underlying ailments can suffer from small fiber neuropathy as well. The most common symptoms include reduced distal temperature and vibration sensitivity in certain people, as well as reduced distal pinprick sensitivity. 

According to studies, a common clinical feature of SFN includes patients who report experiencing electric shock-like pain. Patients also report burning and tingling sensations, and a feeling of pins and needles. These symptoms frequently begin in the feet and move upwards. They could become worse over time.

Patients that suffer from diabetes experience a stocking-glove symmetric pain that starts at the patient’s feet and gradually progresses up to the hands. SFN can also manifest in an asymmetrical pattern affecting that patient’s scalp, proximal limbs, and face as well. The severity of symptoms increases throughout the day. Patients usually experience the worst pain during the night.

Symptoms

Small fiber neuropathy symptoms vary from patient to patient. External stimuli can trigger certain sensory symptoms. Some individuals may experience foot pain when wearing socks or when touching bedsheets. The most common symptom is pain. Other symptoms include the following sensations:

• Prickling, burning, or tingling sensation (paresthesia)
• Loss of sensation
• Short bursts of pain
• Numbness in the lower stomach, legs, or feet
• Hypersensitivity to temperature and touch

The early symptoms of the disease are usually mild, but over time, symptoms progress and worsen. Small fiber neuropathy typically begins at the feet and progresses upward. As mentioned earlier, this distribution is known as “stocking-and-glove.” In the later stages of this condition, the hands may be affected.

Foot and hand pain is the most common early sign of small fiber neuropathy. However, this condition can also impair the body’s ability to feel localized pain and detect temperature.

As the disease progresses, people may experience symptoms in their knees, legs, and arms.

In some instances, small fiber neuropathy interferes with autonomic functions. The body’s autonomic functions include the regulation of digestion, blood pressure, and urinary function.

When autonomic nerve fibers are damaged, the following symptoms may manifest:

• Constipation
• Infrequent or excessive sweating
• Dizziness
• Extremely low blood pressure that could lead to fainting
• Dry mouth
• Dry eyes
• Incontinence (bladder control issues)
• Skin discoloration
• Sexual dysfunction
• Irregular or rapid heartbeat

Small fiber neuropathy symptoms can range from mild to severe. People frequently experience mild symptoms that may go unnoticed in the early stages. Typically, symptoms worsen over time and spread to other areas of the body.