Onychomycosis

　　Onychomycosis is often caused by various fungi such as Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum epidermidis, etc. A few are caused by other filamentous fungi, yeast-like fungi, and yeasts, and occasionally by spore fungi, fusarium, and Trichoderma virens, etc., mostly seen in nails with malnutrition.

　　Onychomycosis can cause pain and discomfort, easily leading to complications such as paronychia, onychalgia, and finger pyoderma. In severe cases, it can cause systemic symptoms of serious diseases such as erysipelas or cellulitis of deep tissues and organs, even threatening life. Women with tinea pedis can be infected with the genital area, leading to difficult-to-cure gynecological diseases such as candidal vaginitis and candidiasis vaginitis.

　　According to the different clinical characteristics of nail damage, onychomycosis can be divided into the following four types:

　　1. Distal subungal onychomycosis
　　This is the most common type. Fungi start to invade the subungal keratin layer of the distal lateral edge, then invade the nail plate bottom surface, gradually causing the nail plate to change color and quality, losing its normal smooth appearance. The accumulation of keratin debris under the nail plate causes the nail plate and nail bed to separate and fall off, or be cut off by the patient, resulting in the complete loss of the nail plate, leaving an overly keratinized nail bed. Some fungi can produce different pigments, such as Phaeosphaeria producing brown, Cladosporium globosum producing black, etc.

　　2. White superficial onychomycosis
　　It is less common. Fungi directly invade the superficial layer of the nail plate, forming small, superficial white spots that enlarge and fuse, eventually causing the nail to become soft and rough, presenting a translucent amber color.

　　3. Proximal subungal onychomycosis
　　Typically seen at the proximal end of the fingernail, it starts as a white spot and can expand into a white patch, showing involvement of the nail plate bottom surface, but the entire nail can be affected, with the primary type being rare. Trauma, diabetes, psoriasis, chronic paronychia, and peripheral vascular diseases can lead to secondary infections of this type.

　　4. Total malnutrition onychomycosis
　　It is the final stage of the development of the above three types, where the entire nail plate is affected.

　　To prevent onychomycosis, attention should be paid to the following aspects in daily life:
　　1. Keep the feet of all family members clean, cool, and dry.
　　2. Try to use showering methods and avoid using alkaline soap.
　　3. Do not wear non-breathable shoes.
　　4. Do not apply poor-quality nail polish.
　　5. Avoid a damp and dark environment.
　　6. Do not share items such as basins, towels, shoes, socks, and nail clippers with sick family members.
　　7. Keep the nails (toes) at a normal length, do not cut them too short, and do not leave sharp corners.
　　8. Do not use the same nail clipper to trim normal and abnormal nails.
　　9. Try not to scratch the bottom of the feet and between the toes with your hands.
　　10. Regularly disinfect the home environment and the patient's belongings.

　　The diagnosis of onychomycosis relies not only on clinical manifestations but also on auxiliary examination, which is an indispensable method. The commonly used examination methods are as follows:

　　1. Fungal Examination Collecting sufficient specimens is the key. For distal subungal type, a spatula, dental scaler, and nail lifter can be used to collect subungal debris. For proximal subungal type, a nail drill or scalpel can be used. For white superficial type, a spatula can be used to scrape the nail debris from the junction of the lesion area and the normal area near the nail bed, and add 10% KOH for direct microscopic examination. The presence of branching hyphae can support the diagnosis. Fungi such as帚霉, 青霉, 曲霉, 头孢, 镰孢, 壳蠕孢, and 白念珠菌 can form hyphae and pseudohyphae and be confused with dermatophytes.

　　2. Histopathology Hyperkeratosis, looseness, keratinocytes arranged in a reticular pattern, and varying degrees of destruction, with visible cracks and cavities. If fine, regular hyphae or arthrospores are seen within the nail plate, it suggests dermatophytosis. The hyphae are mostly horizontal, a few oblique or longitudinal, some growing along the cavity wall, commonly located on the outer or inner layer of the nail plate. When the nail plate is severely damaged, dense arrays of hyphae and spores can be seen throughout the nail plate.

　　Patients with onychomycosis should consume a high-protein diet. A high-protein diet is essential for maintaining healthy nails, and egg yolks are a good source of protein. Oatmeal, nuts, seeds, grains, and dairy products are rich in plant protein. In addition, it is necessary to eat more vegetables and fruits, and fruits and vegetables should account for 50% of daily food intake.

　　The treatment of onychomycosis includes local treatment and systemic treatment. The specific methods of treatment are as follows:
　　First, Local Treatment
　　Applicable to cases with fewer diseased nails. It is possible to persist in applying 5% amorolfine nail polish, 8% cyclopyronamine (cyclohexanone amine ethanol) 30% acetic acid lactic acid iodine solution (10% iodine solution and lactic acid each 50% mixed evenly) or compound salicylic acid ointment. Soak the feet in warm water before applying the medicine, and gently scrape off the diseased nails with a small knife or nail file. Generally, it is necessary to persist for 6 to 12 months. It is also possible to soften the nails with 40% urea ointment and then scrape off the diseased nails, followed by the use of antifungal drugs. It is also possible to remove the diseased nails surgically and then apply antifungal drugs.
　　Second, Systemic Treatment
　　Applicable to patients with multiple diseases of the nails or those who have not responded to local treatment. The duration of treatment should be adjusted according to factors such as the patient's age, the condition of the diseased nails, and the growth rate of the nails.