Mycoses in Diabetic Patients and Treatment of Cutaneous Fungal Infections in Diabetic Patients

Previous studies have shown that people with diabetes have a significantly higher risk of bacterial and fungal infections. In particular, diabetes mellitus is a risk factor for tinea pedis or onychomycosis. Previous studies had found that people with diabetes and onychomycosis have a higher risk of diabetic foot ulcers, but no such significant connection could be demonstrated in recent studies. However, a significant connection was found between onychomycosis and diabetic neuropathy as well as an increased HbA1c value. The most common fungal skin infections in patients with diabetes affect the feet and toenails. Tinea pedis is a dermatophytosis that primarily affects the spaces between the toes and can then spread to the plantar area and ultimately the entire foot. Spread of the fungi to other parts of the body like groins, trunk, even the face, and the scalp is possible. Onychomycosis affects the nail plate and nail bed. Yellow stripes in the longitudinal direction are an indication of matrix involvement in onychomycosis, the maximum form of the fungal nail infection. Dermatophytes are the main pathogens of dermatomycosis and onychomycosis. Trichophyton rubrum and Trichophyton interdigitale are the most frequently isolated causative agent, followed by yeasts (Candida albicans), and sometimes mold fungi like Scopulariopsis brevicaulis or Aspergillus species. Dermatomycological diagnostics are based on microscopic and cultural detection of pathogens. Polymerase chain reaction (PCR) is able to improve sensitivity and specificity of mycological diagnostics. Nail fungal infection is treated with topical and systemic (orally applied) antimycotics. Mild or moderate infections of the nails can be successfully treated with topical antifungals in the form of nail polish. According to the current German S1 Guideline onychomycosis, it is recommended to treat severe onychomycosis by oral terbinafine, fluconazole, or itraconazole. The best therapeutic results in onychomycosis can be achieved when combined topical and systemic antifungal treatment is used.