Why do blisters appear on the soles of the feet every summer?
May 25, 2022
Source: Cainiu Health
Dr. Liu Wan
Introduction
During summer, small blisters may appear on the soles of the feet, which could indicate hyperhidrosis. Due to individual physiological differences, some people experience impaired sweat evaporation from the soles in hot weather, leading to the formation of sweat blisters. Since sweat cannot be promptly excreted through the skin surface, it accumulates beneath the epidermis, resulting in blister formation on the soles. Additionally, such blisters may also stem from vesicular tinea pedis—a fungal infection of the feet—where rapid fungal proliferation triggers blistering on the soles.
In daily life, many patients develop blisters on the soles of their feet each summer, causing significant discomfort and prompting them to seek treatment after identifying the underlying cause. So, what causes recurrent blister formation on the soles specifically during summer?
What Causes Recurrent Blister Formation on the Soles During Summer?
Small blisters appearing on the soles in summer may indicate hyperhidrosis (excessive sweating). Due to individual physiological differences, some people experience impaired sweat evaporation from the soles during hot weather, leading to accumulation of sweat beneath the skin surface. Since this trapped sweat cannot be promptly excreted, it forms intraepidermal vesicles—commonly observed as blisters on the soles. Alternatively, such blisters may stem from vesicular tinea pedis (a fungal infection of the foot), wherein dermatophytes proliferate rapidly, triggering secondary inflammatory responses. This results in spongiform edema and cleavage within the granular layer, manifesting clinically as papules and papulovesicles—i.e., blisters on the soles.
Topical antifungal therapy is recommended: after washing the feet, apply ketoconazole cream or other imidazole-class antifungals—including clotrimazole, propiconazole, naftifine, terbinafine, sertaconazole, oteseconazole, and luliconazole. Among these, allylamine-class antifungals include naftifine, terbinafine, and butenafine.
These agents exhibit potent in vitro antidermatophytic activity; thus, standard treatment courses of 2–4 weeks typically yield favorable clinical outcomes. Other antifungal options include amorolfine, ciclopirox, and liranaftate, which generally require a 4-week treatment course. Keratolytic agents—such as salicylic acid—may be used concomitantly with antifungals, particularly for patients with hyperkeratotic (scaly, thickened) tinea manuum.
Blisters on the soles should never be dismissed lightly. Patients must closely monitor both skin recovery and disease progression and initiate timely treatment. We hope this information proves helpful to you.
