From the Guidelines
Numbness in feet is most commonly caused by diabetic peripheral neuropathy, which can be prevented or delayed with optimal glucose control, as recommended by the most recent guidelines 1. The causes of paresthesia (numbness) in the feet can be multifactorial, including:
- Peripheral neuropathy
- Diabetes
- Vitamin deficiencies (particularly B12)
- Alcohol abuse
- Certain medications (chemotherapy drugs, HIV medications, and some antibiotics)
- Nerve compression (such as tarsal tunnel syndrome)
- Autoimmune disorders like multiple sclerosis
- Infections
- Vascular problems that reduce blood flow to the extremities
- Systemic diseases like kidney disease, liver disease, and hypothyroidism
According to the latest guidelines 1, patients with type 1 diabetes for 5 or more years and all patients with type 2 diabetes should be assessed annually for diabetic peripheral neuropathy (DPN) using the medical history and simple clinical tests. The following clinical tests may be used to assess small- and large-fiber function and protective sensation:
- Small-fiber function: pinprick and temperature sensation
- Large-fiber function: vibration perception and 10-g monofilament
- Protective sensation: 10-g monofilament
Treatment should focus on optimizing glucose control to prevent or delay the development of neuropathy, as well as managing symptoms and improving quality of life 1. This may include:
- Managing diabetes with medications like metformin or insulin
- Vitamin supplementation (B12 1000mcg daily for deficiencies)
- Physical therapy
- Pain medications such as gabapentin (300-1200mg daily) or pregabalin (75-300mg daily) for neuropathic pain
- Lifestyle modifications like regular exercise and avoiding alcohol
It is essential to identify and address the underlying cause of numbness in the feet to prevent further complications and improve patient outcomes, as recommended by the latest guidelines 1.
From the Research
Causes of Paresthesia in the Feet
Paresthesia, or numbness, in the feet can be caused by various factors. Some of the possible causes include:
- Diabetic peripheral neuropathy, which occurs in up to 50% of patients with diabetes mellitus 2, 3, 4
- Vitamin deficiencies, such as vitamin B12 deficiency 2, 5, 6
- Toxins and medications 5, 6
- Poor glycemic control, elevated blood pressure, and obesity 2
- Abnormalities in insulin signaling pathways 4
- Hyperglycemia and disorders of lipid metabolism 4
Diabetic Peripheral Neuropathy
Diabetic peripheral neuropathy is a common complication of diabetes, and its prevalence increases with the duration of diabetes 4. The most common clinical manifestations of diabetic peripheral neuropathy include bilateral limb pain, numbness, and paresthesia 4.
Non-Diabetic Causes
In addition to diabetic peripheral neuropathy, other causes of paresthesia in the feet include vitamin and mineral deficiencies, toxins, and medications 5, 6. These causes can often be treated or prevented with prompt recognition and intervention.
Risk Factors
Several risk factors can increase the likelihood of developing paresthesia in the feet, including poor glycemic control, vitamin B12 deficiency, elevated blood pressure, and obesity 2. Addressing these underlying risk factors is essential to reduce the likelihood of developing neuropathy.