June 2021

Patient Guidance: Common Skin and Nail Conditions of the Lower Extremity – Part 2

Figure. A. Nail plate; B. lunula; C. root; D. sinus; E. matrix; F. nail bed; G. hyponychium; H. free margin. Image by KDS444. Use is per the Creative Commons license CC BY 3.0.

By Paul J. Betschart, DPM

Many foot and ankle specialists focus on the musculoskeletal conditions of patients. Skin and nail conditions of the feet, however, are some of the most common complaints that patients have. This 3-part series describes the most common conditions patients present with to my office and provides some effective treatment options. Part 1 of this series, which appeared last month, focused on common skin conditions. Here we will focus on issues with toenails. Part 3 will focus on conditions related to systemic disease.

Nail Fungus

Nail fungus or onychomycosis is one of most common conditions we treat in podiatry offices. Fungal infections of the nail unit can result in changes of the appearance and quality of the nail plate. The nail plate often becomes discolored, thick, and brittle. Fungal infections usually begin with a break in these barriers through trauma, such as stubbing the toe or cutting nails too short. The fungal organisms gain access to the under surface of the nail and start to grow using the nail plate as food. Keratotic debris that forms can lift up the nail plate further allowing the fungal organisms to spread to more of the nail. If the infection reaches the nail root, nail growth is disrupted, resulting in thickening and irregularity of the nail plate. The fact that the infection is largely under the nail plate makes treating this condition difficult with topical agents alone. A variant of fungal nail infections, white superficial onychomycosis, occurs on the top surface of the nail. This can be easier to treat with topical medications.

The most common class of fungi that causes nail infections are the dermatophytes, meaning, skin lovers. They are the same class of fungi that cause skin fungal infections such as athlete’s foot and ringworm. Other, less common organisms that cause nail infections are saprophytes and yeasts. Diagnosis of infecting organisms is important for guiding treatment decisions. The most accurate testing available today uses genetic sequencing to screen for many different organisms. These tests are very sensitive, requiring small sample amounts. Current testing can identify bacterial involvement as well. Microscopic evaluation can confirm the presence of fungal organisms and rule out other causes of nail dystrophy or disorder.

Treatment of nail fungal infections is usually multimodal. Reducing nail thickness by debridement can help reduce fungal load, enhance topical agent penetration, help reduce symptoms, and improve nail appearance. Topical antifungals such as tolnaftate 1% solution should be applied to the nails 1 – 2 times daily. Penetrating agents such as urea, can help improve the effectiveness of topical antifungals. Oral antifungal therapy is usually needed for most moderate to severe infections. Modern oral agents (pills) are safe to use for most patients. Patients with active liver disease should be monitored closely by their internist during oral antifungal therapy. Safety can be improved by employing a pulsed or interrupted dosing regimen. Agents are typically taken for 1 week at a time with pulses repeated between 1 and 3 months apart. Effectiveness of pulse dosing has been shown to be similar to continuous dosing. The length of treatment varies based on speed of nail growth, with typical treatment regimens lasting 6 – 12 months. New nail grows to replace the infected nail, which is trimmed off the end as growth continues. It is important to continue treatment until the new nail grows in completely. Recurrence is uncommon after complete clearance; however, some people have a higher susceptibility to fungal infections and may need closer observation and preventative measures. The most common adverse effect that concerns most people using antifungals orally is the potential for liver toxicity. This is exceedingly rare with today’s modern antifungals. Anyone with current or suspected liver disease should be considered for liver function testing prior to starting oral antifungals. Monitoring liver function tests during treatment is not necessary if using pulse dosing due to the reduced amount of medication and the interval between pulses. Patients with jaundice, unexplained abdominal pain, or white-colored stools while taking oral antifungals should have repeat liver function tests.

Oral antifungal selection should be based on testing of the nails if possible. The most commonly used oral antifungal used for nail infections is terbinafine. Other effective agents are itraconazole and fluconazole. For patients who cannot or will not take oral antifungals, other methods can be employed to attack the fungus under the nail plate, such as laser therapy. Laser devices of various wavelengths and powers have been employed for nail fungus. In my practice, photodynamic therapy (PDT) using exposure to low-level laser energy after application of photosensitizing dyes such as methylene blue has been highly effective for treating nail fungal and bacterial infections. PDT regimens are typically performed every 2 weeks for 2 – 4 months.

Some patients have repeatedly negative fungal cultures but may have bacteria isolated from their samples. It is unclear at this time whether this bacterial isolation represents a genuine clinical infection or a contamination. More research needs to be done on this subject. I have had success treating patients with fungal negative, bacteria positive nails using topical antibiotic compounds based on the results of genetic sequencing and resistance gene identification. Treatment with these agents is typically needed for 6 – 12 months based on rate of nail growth.

Ingrowing Toenail

Ingrowing toenails are a painful condition that can affect people of all ages. Common causes of ingrowing nails include improper nail trimming, trauma to the toes, ill-fitting footwear, fungal infections of the nail, and genetic nail deformity. The usual signs of ingrowing nails are pain, swelling, and redness of the soft tissues around the nail. Drainage of clear to cloudy fluid from around the nail may be seen. Self-treatment is usually ineffective.

Risks of delayed treatment can include spreading infection, bone infection, and even amputation. Risks are greater in people who are immuno compromised or have poor circulation. Topical and oral antibiotics are commonly prescribed; however, antibiotics alone are rarely curative. Often, the embedded nail fragment acts as a foreign body causing continued pain and swelling even after the infection is treated. Recurrence of the infection is typical without definitive treatment. Partial nail removal along with drainage of any infection is usually curative. This short procedure can be performed easily and safely in an office setting under local anesthetic. The patient or caregiver will need to perform simple wound care to the area daily for 1 – 2 weeks using topical antibiotic compounds. Oral agents are rarely needed unless the infection has spread beyond the nail area. The nail will return to normal shape within 6 months.

In patients with repeated ingrowing nails, permanent removal of the offending portion of the nail may be needed to prevent recurrence. The most common type of permanent partial nail removal is the chemical matrixectomy. This procedure combines the partial nail removal mentioned above with the application of a caustic chemical, such as phenol or sodium hydroxide, to the root area where the nail was removed to prevent regrowth of that part of the nail. Wound care as with the partial nail removal must be performed daily for 2 – 3 weeks. Other techniques to permanently correct ingrowing nails include surgical matrixectomy, radiofrequency ablation, and electric or thermal cautery of the nail root.

Non-surgical techniques to manage ingrowing nails can be effective in those cases where the nail has yet to penetrate the skin around the nail. These include filing of the nail edge, cotton packing of the nail grooves, and taping techniques to pull the skin away from the nail. In response to thickened nails, footwear may generate pressure pushing the nail into the skin. Reducing nail thickness by grinding can help reduce shoe pressure.

Managing underlying nail pathology, such as nail fungus, is also helpful. Non-invasive nail correction devices are another conservative option for addressing the ingrowing nail in its early stages. These devices are applied to the nail and provide a gentle corrective force which, over time, helps to change the shape of the nail, reducing the tendency for it to grow into the skin. The most innovative device of this type today is the Onyfix nail correction system (neubourg healthcare Inc., Toronto, Ontario). This employs an acrylic polymer that is applied to the surface of the nail. Once cured with an LED light, the hardened material exerts a corrective force on the nail as it grows. The material will remain on the nail throughout the growth cycle, typically for 6 – 8 months. Early results have been good with this device. It is especially useful in those who are not surgical candidates or those who are needle phobic.

Occasionally, chronic ingrowing toenails can be caused by underlying bone pathology. The most common bone abnormality associated with ingrowing nails is the subungual exostosis, or bone spur. These are benign growths of bone and cartilage that form on the top of the end toe bone, the distal phalanx. As these lesions get larger, they can press up under the nail bed and affect the shape of the nail. The curved nail shape and the interaction with the shoe toe box can result in chronic ingrowing nails. X-ray examination using a toe isolation technique can help make this diagnosis. Because the cartilage part of the lesion is not visible on x-ray, the lesion could be larger than what appears on X-ray. Subungual exostoses are often related to blunt trauma to the toe. Sometimes these lesions can arise without a cause. Conservative care for this issue consists of wearing higher toe box shoes and cushioning of the toe with shielding materials such as tubular foam or silicone gel. Surgical removal of subungual exostosis can be safely performed in an office setting under local anesthetic, often using minimally invasive techniques through small incisions in the tip of the toe. With very large lesions, skin plasty or removal of redundant skin may be needed to restore the shape of the toe and nail bed area. These procedures occasional require removal of the toenail prior to the procedure. Post-operative care is similar to other forefoot surgical procedures with 2 – 4 weeks in a surgical shoe and suture removal at 2 weeks. Nail regrowth after removal can take 6 months or more.

Nail Trauma

Trauma to the nail area is a common reason for a visit to the emergency department or the doctor’s office. Blunt trauma is most often the cause, either by kicking the foot into something or dropping a heavy object on the toe. The most common resulting issue with blunt toe trauma is blood under the nail, called subungual hematoma. Bleeding under the nail can be caused by chronic toe trauma, such as ill-fitting footwear, as well as acute blunt trauma. Subungual hematoma can be very painful, often worse than the initial trauma. The trapped fluid has nowhere to go and cannot expand the nail plate. Pressure builds up and pushes in to the underlying nail bed causing pain. Rapid pain relief can be achieved by draining the fluid using a needle inserted under the nail plate from the end. This usually does not require anesthetics. Simple gauze dressings to collect any further drainage may be needed for a few days. Further treatment is based on whether there is underlying bone injury, such as a fracture. Some patients with subungual hematoma will eventually lose the toenail. A new nail will begin to grow and will eventually push off the old nail starting from the proximal nail fold area. Loosening nails should be protected from accidental tearing by securing them with tape or an adhesive bandage until they are completely loose. Removal of the partially detached nail after a local anesthetic block can remove this annoyance.

Traumatic nail avulsion is where the nail plate is forcefully detached from the nail bed. This can pe part of the nail or the entire nail. These injuries will bleed a lot due to the vascular nature of the nail bed. Bleeding should be controlled with elevation and a pressure dressing. People taking blood thinners may need to seek medical attention to control bleeding with hemostatic medications. There is controversy on whether a partial traumatic nail avulsion should be converted to complete or if the nail should be left in place to protect the nail bed. My preference is to treat all traumatic nail avulsions as complete and fully remove any partial nail avulsions under a local anesthetic block. This allows for full and accurate inspection of the nail bed for lacerations, which can then be repaired with sutures. This also allows for the ruling out of open fractures of the end toe bone. I find that new nail growth is faster and more even after total nail avulsion versus partial. Penetrating or sharp trauma to the nail area should be approached in the same manner. Nail removal is often needed in these situations to fully assess the injury and repair the damage. Nail regrowth after removal can take 6 – 12 months to return to normal. Injury to the tissues of the nail root area can result in an irregular nail surface that may be permanent.

For any trauma to the nail area, X-ray examination is indicated to evaluate for fractures of the toe bones. Open fractures should be managed aggressively to prevent bone infection. Open fracture wounds should be vigorously cleaned under local anesthetic to remove debris and reduce contamination. Good daily wound care should continue until the wounds heal in 1 – 3 weeks. Reduction and/or fixation of fractures of the end toe bone are not typically needed. Prophylactic antibiotic treatment with a broad-spectrum agent should be used for 10 – 14 days or longer. Serial X-ray examination should be used every 2 weeks to evaluate bone healing and to look for signs of bone infection.

Nail unit trauma that results in significant tissue loss may require advanced tissue products or skin grafts to provide for wound closure. Amniotic tissue grafts and bio-engineered skin substitutes are options that can be employed in the office setting. Skin grafts, if needed, would be performed in the hospital operating room due to the need for anesthesia to obtain the donor tissue, usually from the upper thigh.

Nail irregularity after nail unit trauma is common. Many times, irregularity will resolve with natural nail turnover. In cases of chronic nail dystrophy, where infectious causes such as fungus have been ruled out, permanent total nail removal can be considered. This can provide symptomatic relief as well as improved cosmetic appearance. Calloused skin often forms over the nail bed following permanent nail removal and can look similar to an actual nail. Nail polish can even be applied to this area, although it will not last as long as when on an actual nail

Part 3 of this series, which will appear in the August issue, will focus on nail conditions that can reflect systemic disease.

Paul J. Betschart, DPM, FACFAS, is a podiatrist in private practice in Danbury, Connecticut. A Fellow of the American College of Foot and Ankle Surgeons, his goal is to help his patients achieve optimal health from the ground up.

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