Chapter 5 – DIABETIC NAIL DISEASES

Toenail problems in diabetic patients are of utmost importance since they frequently lead to infections and gangrene, and they often go unnoticed during routine physical examinations. While the primary function of nails is to provide protection and help us appreciate fine touch, they otherwise have little functional importance beyond cosmetic appearance and possibly protecting the toes.

Nails, lacking the moisture of skin, are harder and grow more slowly. They are susceptible to fungal infections, and the skin around the nail (see Fig. 5-1) is prone to bacterial infections. Additionally, slow changes in the nails can sometimes indicate insidious systemic diseases, such as diabetes (see Fig. 5-2), thyroid disorders, or other hormonal imbalances.

Nails require an adequate supply of blood, oxygen, and nutrients to remain healthy. However, when circulation is compromised by Diabetes Mellitus, nails can undergo several pathological changes. In conditions of poor circulation, they tend to become brittle, thin, and may appear whitish.

INGROWN TOENAIL

Initially, a portion of the toenail may penetrate the surrounding skin, creating an ingrown toenail. This condition is typically painful, but in patients with neuropathy, it may go unnoticed. In diabetics, damaged circulation hinders proper healing and promotes necrosis (tissue death) of the surrounding tissue (see Fig. 5-4). Bacteria can multiply rapidly within this necrotic tissue (see Fig. 5-5), setting off a chain reaction of further tissue necrosis. The affected toe then changes from whitish to grayish and eventually turns gangrenous black (see Fig. 5-6). The bone beneath the toenail can become infected and necrotic. This entire process can occur within a few days while the patient remains unaware of the pain due to neuropathy. At this advanced stage, antibiotics are largely ineffective because decreased blood flow prevents them from reaching the gangrenous and infected tissue. The foul smell associated with gangrene is due to anaerobic bacteria, which do not require oxygen to survive and multiply rapidly in oxygen-deprived areas. Ultimately, amputation of the toe becomes necessary.

THEN WHAT ARE THE CAUSES OF INGROWN TOENAIL ON THE FOOT?

One of the most common causes of ingrown toenails is improper nail clipping. Avoid cutting your toenails too short. Another cause is wearing narrow shoes, which can press the edges of the nail against the surrounding skin. For example, in a person with a bunion, the great toe may press against the second toe, causing one or both nails to burrow into the skin (see Fig. 5-7). Ingrown toenails can also occur when the nail grows into the surrounding flesh and is aggravated by tight shoes. Sometimes the nail may bend and compress the nail bed. In some cases, a deformed big toe that is pressed against the floor can also contribute to the development of an ingrown nail.

SO HOW DO YOU PREVENT INGROWN TOENAIL AND INFECTION?

Preventing ingrown toenails is as simple as properly trimming your nails. If you have diabetes, it's important to be under the care of a diabetic foot specialist—a podiatrist. Always use clean, well-maintained nail clippers; avoid using rusty ones, as they can accidentally cut your skin. For patients with extensive arterial disease and neuropathy, it's recommended that someone else trim your toenails, preferably a podiatrist.

Routine visits to your podiatrist are the most effective way to reduce the risk of amputations. Each year, an average of 35,000 to 40,000 diabetic patients undergo amputation of a toe, foot, or leg at a cost of $10 billion—this figure does not include the costs of rehabilitation, prosthetics, lost work time, or disability payments. Alarmingly, some of these amputations are caused by a seemingly minor infected ingrown toenail.

Some people recommend treatments such as filling the nail corners with cotton or cutting the center of the nail into a "V" shape. However, I do not personally endorse these methods, as they do not serve a useful purpose. A better preventive measure is to avoid narrow, pointed shoes in the toe box.

The best way to prevent complications from ingrown toenails is daily self-examination combined with regular monthly visits to your podiatrist.

Check your feet every day. If you find it difficult to inspect your feet, ask a family member for help or use a hand mirror to examine the soles. Always look for any redness around your nails—even if you don’t feel discomfort or pain—because redness and inflammation can be early signs of infection. If you notice these signs, notify your doctor immediately, and avoid attempting to treat the problem yourself by irritating the skin around the ingrown nail.

If you have an ingrown nail, start by soaking your foot in warm salt water for a few minutes, then thoroughly dry your skin, especially between your toes. Next, apply an antibiotic cream to the affected area and wear loose shoes that do not pinch your toes. Avoid soaking your foot in strong antibacterial solutions such as iodine, which, in high concentrations, can damage normal cells and potentially worsen the infection and necrosis in diabetic feet.

FUNGAL INFECTION OF THE TOE NAILS.

Fungal nail infections are very common in diabetics. They are frequently caused by a lack of a proper, closed environment—often due to wearing synthetic socks and shoes that create a humid interior—conditions that promote fungal growth. When the nails become infected, they typically turn yellowish and thick and develop a powdery appearance (See Fig. 5-8).

The fungus in the nail by itself does not usually cause immediate damage (similar to ingrown nails). However, if it becomes secondarily infected with bacteria, it can lead to serious complications. Moreover, fungal infections can significantly alter the overall appearance of the nail, especially when the nail root is affected.

The nail becomes deformed and thickened with debris accumulating under the nail plate. Fungal infections often start in one toenail and may progress to involve other nails; eventually, the fungus can spread to the surrounding skin, resulting in a condition known as "Athlete's Foot" (see Fig. 5-10). Athlete's foot typically causes dryness, peeling of the skin, and the development of multiple small vesicles filled with clear fluid, along with itching—which may not always be apparent in the early stages. The fungal infection usually produces a characteristic musty odor, which can be difficult to treat until the underlying fungal infection is resolved. Foot odor is commonly secondary to these chronic, untreated infections.

Additionally, thick and disfigured nails—especially when confined in a tight shoe—can compress the skin of the toes, leading to irritation that may ulcerate and become infected. This is particularly concerning for diabetic patients suffering from neuropathy, as they may not feel pain despite significant injury. Ulcers may even develop beneath the nail, making them harder to detect. Infections in this area can extend to the bone; the presence of pus under the nail typically indicates a serious infection affecting the toe bone. At this advanced stage, oral antibiotics are often ineffective, particularly in diabetics with poor circulation. Diabetic foot infections frequently lead to thrombosis of the small blood vessels, rapidly progressing to gangrene. When this occurs, amputation of the toe, foot, or even leg may become the only therapeutic option.

When only a small portion of the nail is affected, there are effective treatments available that can address the infection in its early stages.

Removing the yellowish portion of the nail and applying topical antifungal medication can be effective in eradicating the fungus during the early stages of infection. However, once the fungal infection becomes advanced and chronic, it often becomes resistant to treatment—even the strongest topical medications may prove ineffective. In my practice, I frequently prescribe oral antifungal medication. Since toenails grow very slowly—taking more than nine months to fully regrow—oral therapy must be continued for an extended period to achieve a favorable response.

Therefore, rather than relying solely on oral or topical treatments, I recommend the complete surgical removal of the deformed nail along with its root, provided the diabetic patient has adequate blood supply for proper healing. Removing a thickened nail can prevent future complications. Careful and meticulous evaluation by a podiatrist is essential for effective diabetic foot care.

BLOOD UNDER THE NAIL

Blood under the toenail (see Fig. 5-12) is a serious concern for diabetic patients. This condition can occur when shoes compress the toes during activities such as walking, running, or playing tennis. In diabetic individuals with altered sensation due to neuropathy, the lack of pain may allow them to continue these activities, causing the injury to go unnoticed.

The presence of blood under the nail provides a nutrient-rich medium for bacteria, making it a serious condition that requires immediate medical attention—it could cost you your toe, foot, or even leg. While some physicians prefer to drill a hole in the nail to evacuate the blood, I recommend removing the nail completely to fully expose the nail bed. This allows for a thorough examination and removal of any necrotic tissue that could serve as a source of infection. Appropriate antibiotics and local wound care should be initiated immediately. Hospitalization is not necessary unless the condition is complicated by infection, arterial insufficiency, or uncontrolled diabetes.

Additionally, X-rays of the foot should be taken while the nail wound is healing, with subsequent X-rays used to compare healing progress and to exclude any changes in the bone, such as a bone infection. Having a baseline X-ray is invaluable, as it allows for early detection of bone changes during the healing process, enabling timely medical intervention that could ultimately save your foot.

Malignant melanoma, a form of skin cancer, can occasionally occur under the nail. It may appear as a dark blue or purple discoloration, similar in appearance to a hematoma. Although this condition is relatively rare, it is usually detectable by a doctor. It can mimic an infection under the nail and may destroy the nail base without any obvious growth. Fortunately, if diagnosed and treated early, the cure rate for subungual malignant melanoma is higher than that for melanoma of the skin.

Preventing blood accumulation under the nail starts with wearing appropriate shoes. Avoid buying shoes that are merely half a size larger than your normal size, as many diabetic patients mistakenly believe they need extra room for their toes. Instead, choose shoes designed specifically for diabetic patients that offer extra depth, and use appropriate insoles—especially if you engage in regular physical activity. It is also essential to inspect your feet every time you remove your shoes, checking carefully for blisters or any nail problems, as discussed in this chapter.