What causes red blisters on the soles of the feet, and what should be done about it?

Red blisters on the soles of the feet are usually caused by excessive friction or pressure, impaired sweat excretion, athlete's foot (tinea pedis), contact dermatitis, insect bite dermatitis, and other reasons. It is recommended to seek medical attention promptly, identify the underlying cause, and then improve the condition under a doctor's guidance through general management, medication, and other approaches. A detailed analysis is as follows:

1. Excessive Friction and Pressure: Prolonged walking or wearing ill-fitting shoes can lead to repeated rubbing and compression of the skin on the soles, causing tissue fluid to leak out and form red blisters. Immediately switch to loose, breathable flat shoes, avoid prolonged standing or walking, and if the blister remains intact, cover it with clean gauze to reduce further friction.

2. Impaired Sweat Excretion: The soles have highly active sweat glands; wearing non-breathable footwear can trap sweat, irritating the skin and leading to red blisters. Choose absorbent, breathable cotton socks and mesh-top shoes. Soak feet in warm water daily and dry thoroughly afterward to keep the soles dry and avoid moist environments.

3. Athlete’s Foot (Fungal Infection): Fungal infection of the sole skin causes tinea pedis, characterized by red blisters accompanied by itching and flaking. Patients may use antifungal medications such as terbinafine hydrochloride cream, bifonazole cream, or miconazole nitrate cream as directed by a physician. Continue applying until symptoms completely resolve, and avoid sharing foot basins with others to prevent transmission.

4. Contact Dermatitis: Allergic reactions triggered by allergens such as shoe materials or sock dyes can result in red blisters on the soles. Patients should take antihistamines like cetirizine hydrochloride tablets or loratadine capsules, and apply topical corticosteroids such as desonide cream as prescribed. Switch to non-irritating footwear and socks, and avoid known allergens.

5. Insect Bite Dermatitis: Mosquito or insect bites on the sole inject saliva that triggers local inflammation, resulting in red, itchy blisters. As directed by a doctor, patients may use calamine lotion, hydrocortisone butyrate cream, or mometasone furoate cream. Avoid scratching to prevent blister rupture and secondary infection. In severe cases, wound debridement may be necessary to remove infected tissue.

In daily life, do not puncture blisters with needles yourself. If a blister breaks, clean the area with normal saline and apply an antibiotic ointment. Maintain a light diet and reduce intake of spicy or irritating foods. Trim toenails regularly and practice good foot hygiene to lower the risk of infection.