The aim of this study was to determine the prevalence of groin rash among Thai military personnel and to identify associated risk factors, clinical features and patient perceptions. We also evaluated care-seeking behaviour and treatment practices.

Cross-sectional, questionnaire-based study.

Conducted among Thai military personnel in a tropical environment.

A total of 500 male military personnel were recruited between August 2022 and September 2023. Of these, 475 participants were included in the analysis, while 25 were excluded due to non-participation in field training. Eligibility was restricted to those actively engaged in field exercises at the time of study.

Not applicable.

Primary outcome was the prevalence of groin rash, defined by self-report aided by standardised clinical images. Secondary outcomes included risk factors, rash morphology, symptom severity, treatment practices and healthcare-seeking behaviour. Associations were analysed using multivariable logistic regression adjusted for age, body mass index (BMI) and other covariates.

Lifetime prevalence of groin rash was 22.3% (106/475), and the point prevalence was 3.8% (18/475). Among those with rash, 39.6% were classified as probable fungal infections. Independent risk factors included reusing underwear (aOR 2.25; 95% CI 1.27 to 3.99; p=0.005) restricted bathing time (aOR 1.73; 95% CI 1.06 to 2.83; p=0.030) and higher BMI (aOR 1.10; 95% CI 1.02 to 1.42; p=0.030). Most affected participants (54.7%) reported minimal impact on daily life, and only 18.9% sought professional care. Self-medication was common, with 50% using topical over-the-counter antifungals alone, while 16% used a combination of oral and topical drugs. Relapse occurred in 36.1% of cases.

Groin rash is relatively common among young Thai military personnel and is associated with modifiable hygiene-related factors. Only a small proportion of affected individuals appear to present for medical evaluation. Educational interventions emphasising regular laundering and adequate bathing during training may assist in reducing its prevalence.