Treating Difficult Nails In Diabetic Patients

By Peter Blume, DPM, Jared T. Wilkinson, DPM, and Jonathan J. Key, DPM

Due to the nature of the disease, the diabetic patient population has an increased risk of developing nail abnormalities, including onychocryptosis, onychomycosis and other nail structure malformations and injuries. Over one-third of diabetic patients suffer from nail abnormalities and are 2.77 times more likely to have nail mycoses compared to the general population.1 Diabetic patients often develop nephropathy, peripheral neuropathy, retinopathy, cardiovascular disease and impaired circulation, which further exacerbates secondary complications associated with various nail pathologies.2 Due to these sequelae of diabetes and the propensity of developing various nail disorders, the patient with diabetes has a higher risk for complications, including microbial invasion, infection, ulceration and injury. These risks make it important to recognize and treat nail disorders in the diabetic population.3 Mycotic nails can lead to adjacent nail, skin and subungual injury while providing reservoirs for various fungi and increasing the risk of other sequelae and infectious spread.2 The peripheral neuropathy that affects many patients with diabetes may delay recognition and treatment of minor abrasions and lesions. When these abrasions and lesions become infected, it can lead to further ulceration and propagation. Various onychopathies may affect the physical, mental and social health of the patient.4-5 Why It Is Important To Identify Nail Disorders In Patients With Diabetes Onychomycosis occurs in 5.9 percent of people with diabetes (20.8 million people in the United States) compared to 0.8 percent of people without diabetes.6,7 The secondary infection rate of diabetic patients with onychomycosis is 16 percent compared to 6 percent of those without onychomycosis.6 Patients with diabetes and onychomycosis also have a significantly higher occurrence of gangrene and foot ulceration (12.2 percent) as compared to diabetic patients without onychomycosis (3.8 percent).6 Diabetic foot screenings should include the evaluation of nail abnormalities, including onychocryptosis and onychomycosis. Complications of unmonitored nail disorders could lead to severe complications including ulceration and infection. Podiatric physicians should check for nail bed ulcerations resulting from subungual exostoses, distal osteochondromas and endchondromas. Treatment goals should emphasize prevention and active treatment of onychomycosis and other nail disorders in order to prevent associated morbidities and complications. Treatment options include mechanical intervention, pharmacological therapies and surgical intervention. Clinicians must first recognize the nail disorders. The clinical symptoms of onychomycosis include onycholysis, hyperkeratosis, brittle nails, paronychial inflammation and color changes.8 Tenderness to palpation directly on the nail plate in conjunction with associated deformity should trigger a radiographic evaluation of the distal phalanx to rule out exostoses, osteochondromas, endochondromas and suspected osteomyelitis in potential cases of nail bed ulcerations. After ruling out these osseous abnormalities, physicians should identify the causative pathogen. Identification begins with fungal culture or direct microscopy after KOH preparation. Direct visualization determines the presence of hyphal fragments but does not determine the exact organisms. However, results can certify dermatophytic or non-dermatophytic involvement.9 Differential diagnosis of pathogens causing onychomycosis include dermatophytes, non-dermatophytic molds and candidal species. Dermatophyte test media (DTM) can help confirm the clinical diagnosis but the most accurate diagnostic test is a histopathologic examination with periodic acid-Schiff stain (PAS), which has a reported 85 percent rate of accuracy.10 Key Diagnostic Considerations There are four types of fungal infection: distal subungual, white superficial, proximal subungual and candidal onychomycosis.11 Distal subungual onychomycosis, the most common infection, comprises 90 percent of all fungal occurrences. Trichophyton rubrum occurs most often.12Distal subungual onychomycosis. Typically, distal subungual onychomycosis starts by invading the stratum corneum at the hyponychium or lateral nail folds.

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