Foot ulcers are a common complication of poorly controlled diabetes, forming as a result of skin tissue breaking down and exposing the layers underneath. They’re most common under your big toes and the balls of your feet, and they can affect your feet down to the bones.
All people with diabetes can develop foot ulcers and foot pain, but good foot care can help prevent them. Treatment for diabetic foot ulcers and foot pain varies depending on their causes. Discuss any foot pain or discomfort with your doctor to ensure it’s not a serious problem, as infected ulcers can result in amputation if neglected.
Symptoms and Diagnosis
One of the first signs of a foot ulcer is drainage from your foot that might stain your socks or leak out in your shoe. Unusual swelling, irritation, redness, and odors from one or both feet are also common early symptoms of a foot ulcer.
The most visible sign of a serious foot ulcer is black tissue (called eschar) surrounding the ulcer. This forms because of an absence of healthy blood flow to the area around the ulcer. Partial or complete gangrene, which refers to tissue death due to infections, can appear around the ulcer. In this case, odorous discharge, pain, and numbness can occur.
Signs of foot ulcers are not always obvious. Sometimes, you won’t even show symptoms of ulcers until the ulcer has become infected. Talk to your doctor if you begin to see any skin discoloration, especially tissue that has turned black, or feel any pain around an area that appears callused or irritated.
Your doctor will likely identify the seriousness of your ulcer on a scale of 0 to 3 using the following criteria:
0: no ulcer but foot at risk
1: ulcer present but no infection
2: ulcer deep, exposing joints and tendons
3: extensive ulcers or abscesses from infection
Diabetic ulcers are most commonly caused by:
- poor circulation
- high blood sugar (hyperglycemia)
- nerve damage
- irritated or wounded feet
Poor blood circulation is a form of vascular disease in which blood doesn’t flow to your feet efficiently. Poor circulation can also make it more difficult for ulcers to heal.
High glucose levels can slow down the healing process of an infected foot ulcer, so blood sugar management is critical. People with type 2 diabetes often have a harder time fighting off infections from ulcers.
Nerve damage is a long-term effect and can even lead to a loss of feeling in your feet. Damaged nerves can feel tingly and painful at first. Nerve damage reduces your sensitivity to foot pain and results in painless wounds that can cause ulcers.
Ulcers can be identified by drainage from the affected area and sometimes a noticeable lump that isn’t always painful.
Dry skin is common in diabetes. Your feet may be more prone to cracking. Calluses, corns, and bleeding wounds may occur.
All people with diabetes are at risk for foot ulcers, which can have multiple causes. Some factors can increase the risk of foot ulcers, including:
- poorly fitted or poor quality shoes
- poor hygiene (not washing regularly or thoroughly)
- improper trimming of toenails
- alcohol consumption
- eye disease from diabetes
- heart disease
- kidney disease
- tobacco use (inhibits blood circulation)
Diabetic foot ulcers are also most common in older men.
Stay off your feet to prevent pain and ulcers. This is called off-loading, and it’s helpful for all forms of diabetic foot ulcers. Pressure from walking can make an infection worse and an ulcer expand. For people who are overweight, extra pressure may be the cause of ongoing foot pain.
Your doctor may recommend wearing certain items to protect your feet:
- diabetic shoes
- food braces
- compression wraps
- shoe inserts to prevent corns and calluses
Doctors can remove diabetic foot ulcers with a debridement, the removal of dead skin, foreign objects, or infections that may have caused the ulcer.
An infection is a serious complication of a foot ulcer and requires immediate treatment. Not all infections are treated the same way. Tissue surrounding the ulcer may be sent to a lab to determine which antibiotic will help. If your doctor suspects a serious infection, he or she may order an X-ray to look for signs of bone infection.
Infection of a foot ulcer can be prevented with:
- foot baths
- disinfecting the skin around an ulcer
- keeping the ulcer dry with frequent dressing changes
- enzyme treatments
- dressings containing calcium alginates to inhibit bacterial growth
Your doctor may prescribe antibiotics, antiplatelets, or anti-clotting medications to treat your ulcer if the infection progresses even after preventive or anti-pressure treatments. Many of these antibiotics attack Staphylococcus aureus, bacteria known to cause staph infections, or ß-haemolytic Streptococcus, which is normally found in your intestines.
Talk to your doctor about other health conditions you have that might increase your risk of infections by these harmful bacteria, including HIV and liver problems.
Many topical treatments are available for foot ulcers, including:
- dressings containing silver or silver sulphadiazine cream
- polyhexamethylene biguanide (PHMB) gel or solutions
- iodine (either povidone or cadexomer)
- medical grade honey in ointment or gel form
Your doctor may recommend that you seek surgical help for your ulcers. A surgeon can help alleviate pressure around your ulcer by shaving down the bone or removing foot deformities such as bunions or hammertoes.
You will likely not need surgery on your ulcer. However, if no other treatment option can help your ulcer heal or progress further into infection, surgery can prevent your ulcer from becoming worse or leading to amputation.
According to the American Podiatric Medical Association, 14 to 24 percent of Americans with diabetic foot ulcers have amputations. Preventive care is crucial. Closely manage your blood glucose, as your chances of diabetes complications remain low when your blood sugar is stable. You can also help prevent diabetic foot problems by:
- washing your feet every day
- keep toenails adequately trimmed, but not too short
- keeping your feet dry and moisturized
- changing your socks frequently
- seeing a podiatrist for corn and callus removal
- wearing proper-fitting shoes
Foot ulcers can return after they’ve been treated. Scar tissue can become infected if the area is aggravated again, so your doctor may recommend you wear diabetic shoes to prevent ulcers from returning.
When to See Your Doctor
If you begin to see blackened flesh around an area of numbness, see your doctor right away to seek treatment for an infected foot ulcer. If untreated, ulcers can cause abscesses and spread to other areas on your feet and legs. At this point, ulcers can often only be treated by surgery, amputation, or replacement of lost skin by synthetic skin substitutes.
When caught early, foot ulcers are treatable. See a doctor right away if you develop a sore on your foot, as the likelihood of infection increases the longer you wait. Untreatable infections may require amputations.
While your ulcers heal, stay off your feet and follow your treatment plan. Diabetic foot ulcers can take several weeks to heal. Ulcers may take longer to heal if your blood sugar is high and if constant pressure is applied to the ulcer. Remaining on a strict diet and off-loading pressure from your feet is the most effective way to allow your foot ulcers to heal. Once an ulcer has healed, consistent preventive care will help you stop an ulcer from ever returning.