What causes a brown patch of skin on the top of the foot, and what should be done about it?

Generally, brownish skin on the top of the foot may be caused by sunspots, friction-induced pigmentation, post-inflammatory pigmentation, seborrheic keratosis, or pigmented purpuric dermatoses. Depending on the specific situation, patients can choose appropriate treatments such as general care or medication to improve the condition. Detailed analysis is as follows:

1. Sunspots

The top of the foot is often exposed to sunlight. Prolonged ultraviolet radiation stimulates melanocytes to become active, leading to melanin accumulation and formation of brown spots. Wear long-sleeved clothing or apply sunscreen when going outdoors, avoid midday sun exposure, and after cleansing with warm water before bedtime, apply a moisturizer containing vitamin C.

2. Friction-Induced Pigmentation

Tight shoes cause repeated friction on the top of the foot, resulting in thickened stratum corneum and brownish pigment deposition. Switch to loose, breathable footwear to reduce friction on the affected area. Soak feet in warm water daily and apply a moisturizing lotion afterward to soften the thickened skin.

3. Post-Inflammatory Pigmentation

Brownish pigmentation may remain after inflammatory conditions such as eczema or insect bites on the top of the foot have resolved. Follow medical advice to apply hydroquinone cream or azelaic acid cream externally, take oral vitamin E soft capsules, and avoid scratching or irritating the affected area.

4. Seborrheic Keratosis

This results from skin aging causing abnormal proliferation of keratinocytes, forming rough-surfaced brown patches. Under medical guidance, topical tretinoin cream or imiquimod cream may be used, or lesions may be removed via liquid nitrogen cryotherapy.

5. Pigmented Purpuric Dermatoses

Increased capillary permeability leads to red blood cell leakage and rupture, with hemosiderin deposition causing brown discoloration. Elevate the lower limbs to promote circulation, follow medical advice in taking vitamin C tablets, rutin tablets, and calcium supplements, and avoid prolonged standing or sitting.

Brownish skin on the top of the foot is mostly related to pigment deposition. Daily sun protection and moisturization can help prevent worsening. If the lesion rapidly enlarges, has unclear borders, or is accompanied by itching or pain, seek prompt medical evaluation for accurate diagnosis and targeted treatment to achieve effective improvement.