A round ringworm has developed on the foot.

A round fungal-like rash on the foot is usually caused by conditions such as eczema, allergic dermatitis, or athlete's foot (tinea pedis). Patients should use medications under a doctor's guidance. Specific analyses are as follows:

1. Eczema

Eczema is an inflammatory skin condition often related to poor ventilation of the skin on the feet. It can cause localized redness or papules that resemble fungal infections, accompanied by symptoms such as pain, erosion, and oozing. It is recommended that patients apply topical medications such as desonide cream or tacrolimus ointment under medical supervision.

2. Allergic Dermatitis

If a person is allergic to the material of shoes or socks, or has recently come into contact with allergenic substances, an allergic reaction may occur locally, resulting in circular, fungus-like red patches accompanied by itching, swelling, and warmth. Patients should use topical treatments such as calamine lotion or compound acetic acid dexamethasone cream under a doctor’s guidance to relieve symptoms.

3. Athlete's Foot (Tinea Pedis)

This condition is caused by fungal infection and leads to rashes, papules, or vesicular eruptions on the skin of the feet, accompanied by oozing, scaling, and intense itching. Patients should apply antifungal creams such as compound clotrimazole cream or miconazole nitrate cream under medical supervision.

In addition to the common causes listed above, other factors such as dyshidrotic eczema, psoriasis, or syphilis may also be responsible. Patients should seek timely medical attention to prevent worsening of the condition.