The infection caused by dermatophytes invading the smooth skin of the palms, soles, metatarsus, and interdigital spaces is called tinea pedis.

bubble_chart Etiology

The main pathogenic fungi are Trichophyton and Epidermophyton, with common species including Trichophyton rubrum, Trichophyton mentagrophytes, and Epidermophyton floccosum. Among them, Trichophyton rubrum has become the primary causative agent of tinea pedis in China due to its strong resistance and difficulty in control.

The disease is transmitted through contact with pestilence. Activities such as bathing in public baths, wearing shared slippers, using shoes, socks, gloves of infected individuals, or sharing public towels can easily lead to infection. The Bingchuan widespread infection may be attributed to the fact that Trichophyton rubrum or Epidermophyton floccosum often forms arthrospores in skin scales, which can survive harsh environments for extended periods and possess the ability to pestilence others. Additionally, Trichophyton rubrum tends to cause thickening of the stratum corneum and invades vellus hair, making it difficult to cure and prone to recurrence. Furthermore, because the lesions are not highly severe, most patients experience no noticeable symptoms and often neglect timely medical attention, leading to prolonged and unresolved conditions.

bubble_chart Clinical Manifestations

Tinea pedis is commonly seen in adults and can affect both men and women. It often worsens in summer and alleviates in autumn. Without thorough treatment, it may persist for many years. Based on the skin lesion manifestations, it can generally be divided into the following three types, though they may occur simultaneously, alternately, or with one type predominating.

1. The vesicular type is the most common. It frequently presents with needle-sized papulovesicles and vesicles in the interdigital spaces, metatarsus, and lateral margins of the feet, either clustered or scattered. The lesions have thick, shiny walls with varying degrees of inflammatory reaction and cutaneous pruritus. After the vesicles dry, they desquamate, forming small collarette-like or large sheet-like scales, which continuously shed and recur. During stable periods, scaling is often the predominant manifestation.
2. The intertriginous erosive type commonly occurs between the fourth and fifth toes. The stratum corneum becomes macerated, whitish, and softened, peeling off to reveal a red erosive surface or honeycomb-like base, sometimes with slight exudation. This type is prone to secondary infections, such as acute lymphangitis, lymphadenitis, and erysipelas.
3. The hyperkeratotic type is frequently observed on the heels, metatarsus, and lateral margins of the feet. The stratum corneum becomes thickened, rough, scaly, and dry. Subjective symptoms are mild. In winter, rhagades are prone to develop. This type often occurs in patients with a longer disease duration and older age.

bubble_chart Diagnosis

The diagnosis is not difficult based on typical clinical manifestations. However, atypical tinea manuum and pedis is often easily confused with hand and foot eczema, palmoplantar pustulosis, and pompholyx, so differentiation should be noted. Fungal examination is often helpful in confirming the diagnosis.

bubble_chart Treatment Measures

1. For vesicular type, compound benzoic acid liniment, compound resorcinol liniment, 1-3% econazole, miconazole, clotrimazole or ketoconazole cream can be selected as appropriate, applied topically 2-3 times daily. Sometimes 10% glacial acetic acid soaking therapy can be used.
2. For macerated erosive type, generally milder or lower concentration topical antifungal preparations are selected, such as compound resorcinol liniment or the aforementioned imidazole antifungal creams. Sometimes drying powders like foot powder need to be added.
3. For hyperkeratotic type, antifungal ointments or creams are generally preferred, such as compound benzoic acid ointment, imidazole creams or other antifungal medications.