【Rainy Season & Athlete's Foot Survey】33.7% of Adults Have Experienced Tinea Pedis; 74.6% Use Self-Treatment, Risking Spread to Family and Workplace

【Conclusion】Key Findings of the Survey

In short, athlete's foot worsens during the rainy season because dermatophytes (fungi) rapidly multiply in hot, humid environments. Over-the-counter (OTC) medications can be effective for mild cases, but if symptoms persist after two weeks or affect the nails or heels, a visit to a dermatologist is necessary. To prevent spreading the infection to family members, avoid sharing bath mats and slippers, and wash your feet daily.

・74.6% of those who have experienced tinea pedis rely solely on OTC medications, and among them, 62.3% admitted they may have transmitted it to family or cohabitants.

・89.5% of those who visited a dermatologist regret not seeking treatment earlier.

・Only 18.7% were aware of the correct treatment duration (continuing medication for at least one month after symptoms disappear).

Terminology Explanation

What is Tinea Pedis (Athlete’s Foot)?

Tinea pedis is a fungal infection caused by dermatophytes infecting the skin of the feet. There are three main types: interdigital (between toes), vesicular (on the sole), and hyperkeratotic (on the heels). Symptoms include itching, peeling, blisters, and thickened skin. It is estimated that about 1 in 5 Japanese adults suffers from this condition.

What are Dermatophytes?

Dermatophytes are a group of fungi that feed on keratin (a protein in the skin’s outer layer). They thrive in warm, humid conditions and spread through skin flakes or dandruff from infected individuals. They proliferate most rapidly at temperatures of 25–30°C and humidity above 70%.

What is Onychomycosis (Nail Fungus)?

Onychomycosis occurs when dermatophytes infect the nails. It develops in about 10–20% of tinea pedis cases. The nails become cloudy, thickened, and deformed. Over-the-counter topical treatments are largely ineffective, so specialized treatment including oral medication is required.

Comparison of Athlete’s Foot Treatments: OTC vs. Dermatologist-Prescribed Medications

Comparison Item

OTC Medications

Dermatologist-Prescribed Medications

Active Ingredient Concentration

Standard concentration (slightly lower)

Medical-grade concentration (higher)

Recommended Treatment Duration

1–3 months

2–4 weeks (varies by condition)

Effectiveness on Nail Fungus

Almost ineffective

Highly effective when combined with oral medication

Estimated Cost

¥1,500–3,000/month

¥1,000–2,000/month (30% patient co-pay with insurance)

Recurrence Rate

Approx. 50–60%

Approx. 20–30%

Accurate Diagnosis

Self-diagnosis

Confirmed via microscopic examination

*General guidelines; individual results may vary.

IC Clinic (operated by the medical corporation Tekiketsukai), with locations in Shinjuku, Shibuya, Ueno, Ikebukuro, Tokyo, and Omiya, conducted a real-world survey on “athlete’s foot (tinea pedis),” a condition that increasingly troubles people during the rainy season. The survey revealed that although about one in three adults has experienced tinea pedis, most resort to self-treatment, leading to the spread of infection within families and workplaces, as well as chronic conditions and recurrence.

Survey Background

From the rainy season into summer, hot and humid conditions create an ideal environment for dermatophytes—the cause of athlete’s foot—to multiply rapidly. Consultations at our clinic about athlete’s foot typically surge from June onward each year. However, many patients delay visiting due to embarrassment or the belief that OTC medications are sufficient, often only seeking care after the condition has worsened. Recently, with the rise of remote work, more people are walking barefoot at home, increasing cases of household transmission. To understand public awareness and actual behaviors regarding athlete’s foot, we conducted this survey to promote proper treatment education.

Survey Overview

Target: Men and women aged 20–60 across Japan who have experienced symptoms of tinea pedis (athlete’s foot)

Survey Period: May 18–27, 2026

Method: Online survey

Number of Respondents: 300

Survey Results

【Survey Result】74.6% Do Not Visit a Dermatologist and Resort to Self-Treatment

Question: When you first noticed athlete’s foot symptoms, what did you do?

It was found that three out of four people with athlete’s foot experience do not visit a dermatologist and instead rely on self-treatment. Feelings of embarrassment, lack of time, and the belief that OTC medications are sufficient appear to deter visits.

【Survey Result】81.3% Stop Treatment Once Symptoms Disappear, Remaining at High Risk of Recurrence

Question: For those who used OTC medications: When did you stop using the treatment?

Dermatophytes remain dormant in the skin even after symptoms disappear. The Japanese Dermatological Association guidelines recommend continuing treatment for at least one month after symptoms resolve. However, over 80% were unaware of this, creating conditions for early relapse.

【Survey Result】62.3% Believe They May Have Infected Family Members

Question: After developing athlete’s foot, did family members or cohabitants develop similar symptoms?

Over 60% of those with athlete’s foot experience recognize the possibility of secondary infection within the household. Sharing bath mats and slippers, and walking barefoot on floors are the main transmission routes, highlighting the importance of household infection control.

【Survey Result】Only 41.7% Correctly Understand Why Athlete’s Foot Worsens in Rainy Season to Summer

Question: Do you correctly understand why athlete’s foot worsens from rainy season to summer?

Answers like “because of sweating” or “shoes getting stuffy” are half correct, but the core reason is that dermatophytes rapidly multiply at 25–30°C and over 70% humidity. Spreading accurate knowledge is key to prevention and early treatment.

【Survey Result】89.5% of Those Who Visited a Dermatologist Regret Not Going Sooner

Question: For those who have visited a dermatologist: How do you feel about the timing of your visit?

Nearly 90% of those who sought dermatological care realized the importance of early consultation. Many had prolonged OTC use, leading to progression to nail fungus or widespread infection, with numerous respondents saying, “I should have gone to a dermatologist from the start.”

Survey Summary

This survey revealed that 74.6% of athlete’s foot sufferers rely on self-treatment, only 18.7% know the correct treatment duration, and 62.3% have experienced or worry about spreading the infection to family members. Additionally, 89.5% of those who visited a dermatologist regret the delay, suggesting that over-reliance on OTC medications fosters chronic conditions, recurrence, and secondary infections. The rainy to summer season is when dermatophytes are most active, and early, accurate diagnosis and continued proper treatment are essential not only for personal recovery but also for preventing transmission to family and others.

Physician Comment | Dr. Kouta Takakura, IC Clinic

With over 15 years of clinical experience as a dermatologist, I can say that athlete’s foot is a condition that “can always be cured with proper treatment.” However, incomplete self-treatment is the primary cause of chronic conditions and spreading infections.

The mechanism behind worsening athlete’s foot during the rainy season is clear. Dermatophytes multiply most actively at temperatures of 25–30°C and humidity above 70%. Japan’s rainy season perfectly meets these conditions, and prolonged shoe wear causes feet to sweat, creating an ideal breeding ground for fungi.

OTC antifungal ingredients are sometimes the same as prescription ones and can be effective for mild interdigital athlete’s foot. However, the biggest issue is “treatment duration.” The Japanese Dermatological Association’s treatment guidelines recommend continuing topical application for at least one month after symptoms disappear, but this survey found that 81.3% did not follow this. Dermatophytes lie dormant in the skin’s stratum corneum and are not completely eradicated even when symptoms are no longer visible.

Particularly serious is progression to onychomycosis. If tinea pedis is left untreated, about 10–