bubble_chart Overview

Tinea cruris refers to a dermatophyte infection that occurs in the groin, perineum, and perianal areas, essentially being a type of tinea corporis that affects these specific regions.

bubble_chart Etiology

In China, it is mainly caused by Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum canis, and Epidermophyton floccosum. Occasionally, it is caused by Trichophyton schoenleinii, Microsporum ferrugineum, etc.

This disease is primarily transmitted through direct contact with infected individuals, domestic animals with tinea (such as dogs, cats, etc.), or indirect contact with contaminated clothing. It can also result from self-infection (such as pre-existing tinea of the hands, feet, or nails). Long-term use of glucocorticoids, or conditions like diabetes and chronic wasting diseases, increase susceptibility to this condition. Warm climates and humid environments further facilitate its occurrence.

bubble_chart Clinical Manifestations

Tinea corporis commonly occurs on the face, neck, waist, abdomen, buttocks, and limbs. The primary lesions are papules, papulovesicles, or vesicles, ranging from pinhead to mung bean size, gradually expanding outward from the center to form annular or polycyclic patterns. The edges are slightly raised, narrow, and discontinuous, with reduced central inflammation accompanied by scaling or pigmentation. Due to differences in pathogenic fungi and individual variations, the skin lesions may vary. For example, lesions caused by anthropophilic Trichophyton rubrum often appear as large patches with fewer numbers, while lesions caused by zoophilic Microsporum canis or Microsporum gypseum exhibit more pronounced inflammation, often dominated by vesicles, with fewer lesions but greater numbers. The condition is accompanied by cutaneous pruritus, and prolonged scratching may lead to localized eczema-like changes or secondary bacterial infections. This disease can occur at any age but is more common in young and middle-aged males. Symptoms often flare up or worsen in summer and alleviate or subside in winter.

Tinea cruris can occur unilaterally or bilaterally, with basic lesions similar to tinea corporis. However, due to the warm, moist, and friction-prone nature of the area, it often manifests as erythema with clearly defined borders and pronounced inflammation on the lower side. In chronic cases, the lesions may lose their typical appearance or become thickened and lichenified due to scratching.

bubble_chart Diagnosis

Based on the typical skin lesion manifestations, diagnosis is generally not difficult. Taking scales from the edge of the lesion for direct fungal microscopy can confirm the diagnosis, but a negative result does not necessarily rule it out. Sometimes repeated examinations or fungal culture are required. This condition should sometimes be differentiated from annular erythema, pityriasis rosea, eczema, neurodermatitis, or erythema intertrigo. Fungal testing can aid in the final diagnosis.

bubble_chart Treatment Measures

1. Drug therapy is the main treatment. Compound benzoic acid liniment (Whitfield's solution), compound resorcinol liniment (Castellani's paint), 3% miconazole cream, 1-2% clotrimazole cream, ketoconazole cream, etc., can be applied topically twice daily as appropriate. Continue for 2-4 weeks. After the skin lesions subside, continue medication for another 2 weeks to prevent recurrence. For tinea cruris and tinea corporis in infants and young children, milder medications should be selected.
2. For patients with extensive skin lesions or poor response to topical treatment alone, oral griseofulvin can be added, with adults taking 0.6-0.8g daily for 2-4 weeks, or ketoconazole 0.2g for 2-4 weeks. Itraconazole or terbinafine may also be used as appropriate.
3. If accompanied by tinea manuum, tinea pedis, or onychomycosis, concurrent treatment is necessary.
4. Maintain personal hygiene, avoid using bath basins, slippers, towels, or undergarments of tinea patients, and avoid contact with dogs or cats infected with tinea.