Diabetes and Wound Healing: Why Is It Slower?

Diabetes mellitus is a chronic disease that is becoming more prevalent worldwide. Diabetes causes high blood sugar, which is harmful to health in many ways.

As of 2015, 30.3 million people in the United States, or about 9.4 percent of the population, had diabetes. Unfortunately, more than 1 in 4 people with diabetes don’t know they have it.

Having undiagnosed diabetes increases the risk of diabetes-related complications such as kidney disease, heart disease, amputations, and more.

Many people also have prediabetes, a condition where blood sugars are slightly elevated but not high enough to be considered diabetes. Having prediabetes is a significant risk factor for eventually developing type 2 diabetes. The U.S. Centers for Disease Control (CDC) estimates that up to 30% of people with prediabetes will develop type 2 diabetes within five years of their prediabetes diagnosis.

The majority of people with diabetes have type 2, which typically affects older adults and can be related to multiple known risk factors, including race, weight, and some lifestyle factors. Type 1 diabetes is more rare as it’s an autoimmune disorder. Type 1 usually occurs before age 18, which is why it’s also referred to as juvenile diabetes. Type 1 diabetes affects about 2-5% of the world’s population or about 1 in 300 American adults before the age of 18. 

High blood sugar impacts all of the body’s systems and can cause complications if blood sugars are chronically elevated. One of the ways diabetes can impact the body is through delayed wound healing.

How does diabetes affect your body?

Blood glucose, or blood sugar, is the primary energy “currency” used by the body’s cells. In order for the glucose to enter the cell, it requires a hormone called insulin, which is produced by the pancreas.

Cells have insulin receptors that insulin can bind to, letting the glucose enter the cell from the bloodstream. Another way to think of it is that insulin is the key to enter the cell “door,” which has an insulin receptor “doorknob.” 

Type 2 diabetes usually occurs from insulin resistance, which is when cells don’t respond to or use insulin effectively. This can lead to an insulin deficiency from the pancreas working harder to produce more insulin in response to high blood sugar levels. Without enough insulin, the glucose molecules are unable to enter the cells as they should. When this occurs, glucose accumulates in the bloodstream and leads to hyperglycemia or high blood sugar.

Type 1 diabetes is less common and is an autoimmune disease. Autoimmune diseases occur when the immune system mistakenly attacks normal and healthy parts of the body. In the case of type 1 diabetes, the beta cells of the pancreas are destroyed, leading to inadequate amounts of insulin production.

When blood sugar levels are high, it damages the blood vessels supplying blood to the body. It’s similar to the metal being corroded by rust – the longer metal is exposed to water, the more likely it is to rust. Similarly, the longer a blood vessel is exposed to high blood sugar, the more likely it is to be damaged. When blood vessels are damaged by blood sugar, they can become more stiff and hard, and blood flow may be reduced. 

Left untreated, chronic high blood sugar can cause multiple complications, such as:

• Cardiovascular (heart) disease
  
  
• Nerve damage (neuropathy) – high blood sugar can injure the walls of the tiny blood vessels (capillaries) that supply the nerves, especially in the legs. This can cause tingling, numbness, burning, or pain that often begins at the toes or fingers’ tips and can spread and worsen.
  
• Kidney damage (nephropathy)
  
  
• Eye damage (retinopathy)
  
  
• Foot damage
  
  
• Skin conditions and poor wound healing
  
  
• Hearing impairment
  
  
• Increased risk of Alzheimer’s disease (dementia)
  
  
• Depression

Why is wound healing slower?

Immune response in people with type 2 diabetes

Inflammation can be a useful protective mechanism used by the immune system. Inflammation helps the body fight off things that might harm it, such as infections, injuries, and toxins.

When something causes a threat to cells, such as a wound, the immune system releases chemicals to trigger this immune response. This is one of the reasons why injuries are often swollen during the first few days after it occurs – it’s inflammation in action. However, when inflammation is prolonged, wound healing can be delayed. 

Researchers have found that people with type 2 diabetes seem to have an altered immune response. One study found that people with diabetes had lower levels of a gene responsible for wound healing present in their foot ulcers. People with type 2 diabetes are generally thought to have an altered immune response, making them more susceptible to illness, infections, and other conditions where pathogens invade the body.

When the immune system can’t fight off things like bacteria, wounds are more likely to become infected. Infected wounds are more complicated and take longer to heal.

Neuropathy

Diabetes can damage the nerves responsible for allowing people to have normal sensation in their extremities, especially the hands and feet. This is called peripheral neuropathy and has symptoms such as:

• Gradual onset of numbness, prickling, or tingling in your feet or hands, which can spread upward into the legs and arms.
  
  
• Sharp, jabbing, throbbing, or burning pain.
  
  
• Extreme sensitivity to touch.
  
  
• Pain during activities that shouldn’t cause pain, such as foot pain while bearing weight or feet under a blanket.
  
  
• Lack of coordination and falling.
  
  
• Muscle weakness.
  
  
• Feeling as if gloves and socks are being worn, but they aren’t.

People with neuropathy are less likely to notice when they have an injury. This often starts with something small like a blister from poorly-fitting shoes. Without being able to feel the blister’s pain, the person will likely go on wearing the shoes, and the injury will worsen and be more difficult to heal due to the severity of tissue damage.

Poor circulation

Blood flow can be altered when the lining of the vessels become damaged from chronic hyperglycemia. When part of the body has reduced blood flow, it has reduced access to healthy blood containing oxygen and nutrients responsible for healing. Damaged tissue that doesn’t have adequate blood flow will be slow to heal and can even die. 

Circulation in the legs tends to be negatively impacted more severely than other body parts, which is one of the reasons ulcers tend to appear on the feet.

Another main reason foot ulcers occur is from diabetic neuropathy, which inhibits a person’s ability to feel the pain from the wound, which often delays treatment. Native Americans, African Americans, Hispanics, and older men are more likely to develop foot ulcers, as well as those who are overweight and/or use tobacco. 

Peripheral artery disease (PAD) is common in people with diabetes and occurs when arteries are blocked by plaque, restricting blood flow. The term for arteries narrowing from plaque is called atherosclerosis and is another cause of poor circulation. It’s similar to how heart disease occurs from blocked arteries around the heart, leading to a heart attack. People with PAD are at much higher risk of having a heart attack and stroke due to the arteries’ narrowing.

Foot deformities

People with diabetes can develop foot deformities such as Charcot’s foot. These deformities put more pressure on parts of the feet, leading to ulceration and wounds. Charcot’s foot is more common in people with neuropathy.

Complications

One of the most common complications from delayed wound healing in people with diabetes is foot ulcers, which are open wounds or sores on the bottom of the feet. It’s estimated that 15% of people with diabetes will develop diabetic foot ulceration. 

When wounds are slow to heal, it can lead to the need for amputations. Around 230 people with diabetes undergo amputation each day in the United States. Foot and leg amputations are common due to the prevalence of diabetic foot ulcers.

People with diabetes are more likely to suffer from infected wounds, leading to their own problems. Infections can lead to a severe condition called sepsis, which is when the immune system can attack the entire body. Diabetes is estimated to constitute around 21% of all sepsis patients, making infections a significant cause of death in people with diabetes.

How to treat slow-healing wounds

Chronic wounds that are slow to heal should be evaluated by a healthcare professional right away. Some patients with more serious wounds may be referred to a wound care clinic, where people specializing in wounds can offer the most appropriate therapy. A podiatrist is a healthcare professional specializing in foot issues, so they are often involved in diabetic wound care relating to the feet as well.

Both oral and topical antibiotics may be recommended to aid in healing and fight off infection. A healthcare provider may prescribe these, but some are available over-the-counter.

Wounds should be cleaned and dressed as often as advised by a healthcare provider. Keeping the wound clean will prevent further infection and aid in wound healing, and keeping it covered will reduce the likelihood of further contamination by germs and debris. Covering injuries can also help keep them moist, which aids in healing.

Some wounds may need debridement, which removes dead skin and tissue to allow the wound to better heal. This is done by a healthcare professional and shouldn’t be attempted by the person with the wound.

Off-loading is the term for taking pressure off the area to allow better healing. This is done by offsetting weight in order to put less pressure on the impacted wound. For instance, someone with a foot ulcer may need to use crutches to aid in the healing.

One of the most important aspects of wound healing is to control blood glucose levels. While wound dressings and creams can help aid in healing, there is no substitute for the importance of good blood sugar control. When blood sugar levels are normalized, diabetic wound healing is improved. Working with healthcare providers such as primary care physicians, endocrinologists, diabetes educators, and dietitians can promote healthy blood sugar levels.

A more advanced method for wound healing is utilizing hyperbaric oxygen therapy. This involves exposing the body to 100% oxygen levels to help aid in healing. Wounds require oxygen for healing, which is why this may help speed wound healing.

When to see your doctor

A healthcare provider should be notified any time there is a wound present that doesn’t seem to be healing. A diabetic foot ulcer should be evaluated right away. Other signs that warrant a visit with a doctor include:

• The cut’s edges are jagged or gape open, the cut is deep (1/4 inch or more), or you can see fat or muscle. These are signs that stitches may be needed.
  
  
• You can’t get all of the dirt or debris out of the wound, or the wound was caused by something very dirty or rusty.
  
  
• You have a puncture wound or a cut and haven’t had a tetanus shot in the past 5 years.
  
  
• The wound is from an animal or human bite.
  
  
• The injured area feels numb.
  
  
• The presence of a fever or any other signs of infection.
  
  
• If blood sugar levels are higher than usual accompanying the wound.

How to promote long-term healing

The best way to promote long-term wound healing is through prevention. There are many ways people with diabetes can prevent wounds, such as:

Regular foot checks

It’s recommended that all people with diabetes take time to inspect their feet each day to check for blisters, wounds, or other red flag warning signs. This is especially important for people who also suffer from neuropathy.

The American Diabetes Association recommends an annual comprehensive foot exam for all people with diabetes. This can involve checking pulses in the feet and testing for neuropathy using a microfilament test. 

Proper-fitting shoes

People with diabetes may need special shoes that help reduce pressure in the feet, helping prevent foot ulcers. Insurance companies often cover diabetic shoes as a benefit because of the importance of properly-fitting footwear.

It’s also recommended that people with diabetes don’t walk barefoot, increasing the chances of injury to the feet. Shoes should also be checked for foreign objects before putting them on.

Good skincare

Skin complications can increase the likelihood of wounds. The American Diabetes Association recommends following good skincare habits, including:

• Keep skin clean and dry. 
  
  
• Avoid very hot baths and showers. If the skin is dry, avoid bubble baths. Moisturizing soaps may help. Afterward, use a standard skin lotion, but don’t put creams between toes. The extra moisture there can encourage fungus to grow.
  
  
• Prevent dry skin. Scratching dry or itchy skin can open it up and allow infection to set in. Moisturize your skin to prevent chapping, especially in cold or windy weather.
  
  
• Treat cuts right away-Wash minor cuts with soap and water. Only use an antibiotic cream or ointment if your doctor says it’s okay-cover minor cuts with sterile gauze. See a doctor right away if you get a major cut, burn, or infection.
  
  
• During cold, dry months, keep your home more humid. Bathe less during this weather, if possible.
  
  
• Use mild shampoos. 
  
  
• Do not use feminine hygiene sprays.
  
  
• See a dermatologist (skin doctor) about skin problems if you cannot solve them yourself.

Promote healthy blood sugar levels. 

This is one of the most important aspects of wound prevention. There are many ways to achieve healthy blood sugar levels, including:

• Use of medications as prescribed. Common drugs treating diabetes include insulin, metformin, sulfonylureas, DPP-4 inhibitors, GLP-1 receptor agonists, among many others.
  
  
• Monitoring blood sugar levels. Checking blood sugar levels regularly at home, as well as having routine glucose screenings such as the hemoglobin A1c test, usually leads to better outcomes than people who don’t routinely monitor blood sugars. 
  
  
• Healthy eating habits. Eating a nutritious diet, such as a Mediterranean diet, has been shown to improve health outcomes. An added bonus is that this eating style is associated with reduced levels of inflammation, which may help promote better-wound healing. A Mediterranean diet consists of foods like:
  • Vegetables
    
    
  • Fruits
    
    
  • Nuts and seeds
    
    
  • Legumes
    
    
  • Tubers such as potatoes, parsnips, etc.
    
    
  • Whole grains
    
    
  • Fish and seafood
    
    
  • Poultry
    
    
  • Eggs
    
    
  • Dairy
    
    
  • Herbs and spices
    
    
  • Healthy fats such as avocados and olive oil

A Mediterranean diet is also low in both added and refined sugar, which should be limited to around 25-35 grams per day or less.

• Being physically active. Engaging in at least 30 minutes of moderate to vigorous physical activity most days (aiming for at least 150 minutes per week) can help promote healthy blood sugar levels. Strength and resistance training can further improve blood sugar.

Conclusion

People with diabetes are at increased risk of wounds being slow to heal. The main reason for this is due to high blood sugar, which negatively impacts the healing process and increases the likelihood of complications such as infections and amputations. People with diabetes also have impaired immune responses, leading to delayed healing time and increased risk of infections.

Wounds are often treated with antibiotics to minimize the chance of infection, as well as keeping the wound clean and dressed. Dermatologists, podiatrists, and other healthcare professionals can aid in wound care for people with diabetes.

The best way to prevent poorly-healing wounds is to promote healthy blood sugar levels. Regular foot checks, good skincare as well as practicing healthy lifestyle habits such as eating healthy and being active can all help prevent complications from poorly-healing wounds.

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