What causes athlete's foot,烂脚趾缝 (cracked and broken skin between the toes), itching, and ulceration?

In general, itching, erosion, and ulceration between the toes caused by athlete's foot may be due to various factors, including thickened stratum corneum, excessive sweating, allergies, eczema, and systemic lupus erythematosus. If in doubt, it is advisable to seek medical consultation promptly. The detailed analysis is as follows:

1. Thickened Stratum Corneum

An excessively thick stratum corneum reduces skin breathability and increases local humidity, creating favorable conditions for fungal growth. Meanwhile, cracks in the thickened layer provide entry points for fungi. This condition may be accompanied by symptoms such as rough skin and scaling. It is recommended to regularly remove excess keratin and maintain cleanliness and dryness of the skin between the toes, while avoiding overly harsh exfoliating products.

2. Excessive Sweating

Some individuals naturally have overactive sweat glands, especially in the feet, which can lead to a moist environment between the toes—ideal for fungal proliferation. This may result in infection, foot odor, and itching between the toes. It is advised to keep feet dry, change socks frequently, and use highly absorbent insoles.

3. Allergy

Certain chemicals, detergents, fabrics, and other substances may trigger allergic reactions on the feet. Upon contact with the skin, these irritants or allergens can cause allergic or inflammatory responses, damaging the skin barrier and leading to symptoms such as itching and ulceration. Additional symptoms may include redness, swelling, pain, and a burning sensation. Avoid contact with irritants and, under medical guidance, consider using treatments such as hydrocortisone cream, desonide cream, or loratadine tablets.

4. Eczema

Eczema is an inflammatory skin reaction triggered by various internal and external factors. Foot eczema may cause itching and ulceration between the toes, particularly in damp and hot environments. Besides itching and erosion, symptoms may include erythema, papules, and vesicles. Under medical supervision, topical anti-inflammatory medications such as mometasone furoate cream, compound dexamethasone acetate cream, or halometasone cream may be applied.

5. Systemic Lupus Erythematosus (SLE)

Systemic lupus erythematosus, often influenced by genetic and other factors, causes abnormal immune responses that attack normal skin tissues, resulting in skin inflammation and impaired skin barrier function. When affecting the feet, this may manifest as athlete’s foot-like symptoms and ulceration, along with systemic symptoms such as fever and joint pain. Treatment should be conducted under medical supervision using medications such as methylprednisolone tablets, warfarin sodium tablets, and mycophenolate mofetil capsules.

It is recommended to pay attention to bodily responses in daily life. If signs of allergy are suspected, discontinue contact with or consumption of potentially allergenic substances immediately. Additionally, maintain clean and dry feet by frequently changing socks and shoes.