What skin condition is indicated by red itchy patches on the bottom of the feet?

The presence of red, itchy patches on the bottom of the feet is most commonly associated with tinea pedis, which is a fungal infection often known as athlete's foot. This condition is characterized by the appearance of red, inflamed areas that may also be scaly and itchy. The fungi that cause tinea pedis thrive in warm, moist environments, such as between the toes or on the soles of the feet, making them particularly susceptible to infection.

In contrast, onychomycosis primarily affects the nails, causing them to become discolored, thickened, and possibly crumble. Psoriasis is a chronic autoimmune condition that can cause red patches with silvery scales, and it can appear on the feet but is not primarily characterized by itching or red patches on the soles. Dermatitis, while it can cause itchy and inflamed skin, typically presents with a different pattern and may be associated with other factors such as allergies, irritants, or contact exposure.

Therefore, tinea pedis is the most accurate diagnosis for red itchy patches specifically located on the bottom of the feet.