Foot Mycoses Among Tanzanian Footballers: A Clinico‐Epidemiological Study

ABSTRACT

Background

Superficial foot mycoses (SFM), including onychomycosis and tinea pedis, are common fungal infections among athletes, particularly professional footballers, owing to repetitive trauma, occlusive footwear, communal facilities, and hygiene practices. These infections may cause discomfort, nail deformity, and impaired athletic performance.

Objectives

To determine the prevalence, clinical spectrum, and factors associated with SFM among professional footballers in the Tanzanian Premier League between 13th August 2024 to 12th August 2025.

Methods

A community‐based cross‐sectional study was conducted among 314 professional footballers from 13 Premier League clubs (9 males and 4 females). Clinical examinations and KOH microscopy were performed at Mwananyamala Regional Referral Hospital, Dar es Salaam. Socio‐demographic and clinical data were collected using structured questionnaires and checklists. Modified Poisson regression was used to identify factors associated with SFM.

Results

The overall prevalence of SFM was 36.9%. Onychomycosis occurred in 17.2%, tinea pedis in 12.4%, and co‐infections in 7.3%. Distal and lateral subungual onychomycosis (16.9%) and interdigital tinea pedis (12.4%) were the predominant clinical forms. Inter‐toe maceration (48.3%), toenail dystrophy (45.7%), and itchiness (44.0%) were the most frequent symptoms. Significant associated factors included toenail trauma (APR = 2.00, p < 0.001), sharing socks (APR = 1.42, p = 0.032), communal shower use (APR = 2.98, p = 0.007), and family history of SFM (APR = 1.57, p = 0.001).

Conclusion

SFM is highly prevalent among Tanzanian Premier League footballers. Modifiable hygiene practices and environmental exposures significantly increase infection risk, highlighting the need for targeted health education, improved sanitation, and routine screening programs.

1. Introduction

Superficial foot mycoses (SFM) are the most common skin conditions affecting 3% of the global population with onychomycosis and tinea pedis representing the most prevalent clinical entities. Among the population at risk, footballers are particularly vulnerable due to the warm, moist microenvironment within footwear, repetitive nail and skin trauma associated with high‐intensity activity, and communal bathing practices [1, 2]. As it is asymptomatic and non‐life‐threatening, SFM is usually neglected by footballers till complication occurs like pain, discomfort, and activity limitations with potential progression to more serious infections that may impair the performance of footballers [3].

Despite the growing awareness among athletes' health care providers, epidemiological data from Sub‐Saharan Africa remain scarce. However, differences in climate, training environments, hygiene practices, and lack of information on preventive measures may substantially influence the disease patterns. This study aimed to determine the prevalence, clinical spectrum, and factors associated with SFM among professional footballers in the Tanzanian Premier League.

2. Materials and Methods

Following the acquisition of ethical clearance (PG 55/2024) from the KCMC University Ethical and Research review Committee and official permission from the Tanzania Football Premier League Board, we started to conduct our research from 13th August 2024 to 12th August 2025. Study activities were done in Dar es Salaam, Tanzania.

2.1. Sample Size

Tanzania Premier League comprises 16 male teams and 10 female teams, with each team mandated to register a minimum of 25 players. This yields a minimum total of 650 registered footballers eligible to participate in the league. We planned to enrol at least half of each team, female and male, representing 320 footballers. Following the acquisition of official permission from the Tanzania Football Premier League Board, all teams were formally invited to participate in the study through official correspondence. Finally, 9 male and 4 female teams accepted to participate.

2.2. Study Procedures

Upon acceptance, team visits were coordinated with each team's manager to enrol participants. Informed consent and assent were obtained before any activities. Standardised dermatological examinations were performed by the Principal Investigator. In suspected SFM, collection of nail clippings and skin scrapings was taken in onychomycosis and tinea pedis respectively. Specimens were collected and transported to Mwananyamala Regional Referral Hospital (MRRH) for potassium hydroxide (KOH) microscopy examination. Superficial fungal mycosis (SFM) was defined as the presence of characteristic clinical changes together with positive direct microscopy findings. The detection of fungal hyphae or other characteristic fungal elements on KOH microscopy was considered confirmatory of SFM infection. It was not possible to access laboratory facilities to culture the skin and nail samples, a common problem in the region [4].

2.3. Data Collection and Analysis

A questionnaire including clinical information and laboratory results was used to collect data of each footballer. Data were captured and analysed using Statistical Package for Social Sciences (SPSS) version 27.0. Descriptive statistics were performed, with categorical variables summarised using frequencies and proportions, while numerical variables were presented using means and their respective measures of dispersion. Modified Poisson regression analysis was conducted to identify factors associated with superficial foot mycoses among professional footballers in the Tanzania Premier League. A p of < 0.05 was considered statistically significant.

3. Results

A total of 314 footballers were enrolled in the study, among whom 222 were male (70.7%), and 92 were female (29.3%). The participant age ranged between 17 and 36 (SD 24 ± 4). The proportion of participants who had attained secondary education was 65% (204/314), and two‐thirds 74.5% (234/314) were single.

3.1. Prevalence of Superficial Foot Mycosis

Among 314 participants (222 males, 92 females), onychomycosis was the most prevalent superficial foot mycosis, affecting 17.2% of participants, where females accounted for 20.7% while 15.8% were males. The most frequent subtype was DLSO (16.9%). Tinea pedis was diagnosed in 39 participants (12.4%), whereas in males it was 12.6% and in females it was 12.0%. The interdigital type was the most prevalent subtype affecting all participants with tinea pedis (Table 1). A total of 23 professional players (7.3%) were diagnosed with both tinea pedis and onychomycosis with a higher prevalence in males (8.6%) compared to females (4.3%). Mixed pattern infections involving multiple subtypes of onychomycosis and tinea pedis were observed and primarily in male footballers. These included combinations such as TDO+PSO+DLSO+WSO+interdigital (5 cases; 1.6%) and TDO+PSO+DLSO+vesicular bullous (1 case; 0.3%).

TABLE 1.

Clinical spectrum of superficial foot mycosis among professional footballers.

Clinical spectrum	Total (N = 314) n (%)	Sex
		Male (n = 222) n (%)	Female (n = 92) n (%)
Onychomycosis	54 (17.2)	35 (15.8)	19 (20.7)
DLSO	53 (16.9)	42 (18.9)	11 (12.0)
TDO	47 (15.0)	33 (14.9)	14 (15.2)
PSO	24 (7.6)	17 (7.7)	7 (7.6)
WSO	7 (2.2)	7 (3.2)	0 (0.0)
Tinea pedis	39 (12.4)	28 (12.6)	11 (12.0)
Interdigital	39 (12.4)	28 (12.6)	11 (12.0)
Hyperkeratotic (moccasin)	2 (0.6)	2 (0.9)	0 (0.0)
Vesicle bullous	1 (0.3)	0 (0.0)	1 (1.1)
Onychomycosis+Tinea pedis	23 (7.3)	19 (8.6)	4 (4.3)
TDO+PSO+DLSO+WSO+interdigital	5 (1.6)	5 (2.3)	0 (0.0)
DLSO+interdigital	5 (0.6)	3 (1.3)	2 (2.2)
TDO+PSO+DLSO+interdigital	4 (1.3)	2 (0.9)	2 (2.2)
TDO+DLSO+ interdigital	4 (1.3)	4 (1.8)	0 (0.0)
TDO+interdigital	2 (0.6)	1 (0.5)	1 (1.1)
DLSO+hyperkeratotic	1 (0.3)	1 (0.5)	0 (0.0)
DLSO+interdigital+hyperkeratotic	1 (0.3)	1 (0.5)	0 (0.0)
TDO+PSO+DLSO+vesicle bullous	1 (0.3)	0 (0.0)	1 (1.1)
Normal	198 (63.1)	140 (63.0)	58 (63.0)

Abbreviations: DLSO, Distal and lateral subungual onychomycosis; PSO, proximal subungual onychomycosis; TDO, Total dystrophy onychomycosis; WSO, white subungual onychomycosis.

Multivariable analysis revealed several significant predictors of SFM among footballers such as sharing socks, showering in the club changing room, toe nail trauma and family history of SFM. Those who shared socks had 39% higher prevalence of having SFM compared to those who do not share socks (APR = 1.42, 95% CI: 1.03–1.98, p = 0.032). Footballers who shower in the club changing room had nearly three times higher prevalence of acquiring SFM compared with those who do not shower in the club changing rooms (APR = 2.98, 95% CI: 1.34–6.65, p = 0.007). Footballers with toe‐nail trauma had twice times higher prevalence of acquiring SFM compared to those without toe‐nail trauma (APR = 2.00, 95% CI: 1.42–2.82, p < 0.001). Footballers with a family history of SFM had a 57% higher prevalence of having SFM compared with those with no family history of SFM (APR = 1.57, 95% CI = 1.19–2.07, p = 0.001) (Table 2).

TABLE 2.

Associated factors with superficial foot mycosis among professional footballers (N = 314).

Variable	Total N	SFM n (%)	CPR (95% CI)	p	APR (95% CI)	p
Sharing football boots
No	254	64 (25.2)	Ref		Ref
Yes	60	52 (86.7)	3.58 (2.83–4.52)	0.6	2.06 (1.36–3.12)	0.08
Sharing socks
No	263	68 (25.9)	Ref		Ref
Yes	51	48 (94.1)	3.93 (3.15–4.91)	< 0.001	1.42 (1.03–1.98)	0.032*
Showering in club changing room
No	227	49 (21.6)	Ref		Ref
Yes	86	67 (77.9)	3.60 (2.49–5.21)	< 0.001	2.98 (1.34–6.65)	0.007*
Toe nail trauma
No	241	52 (21.6)	Ref		Ref
Yes	73	64 (87.7)	4.05 (3.13–5.23)	< 0.001	2.00 (1.42–2.82)	< 0.001*
Family history of SFM
No	279	83 (29.7)	Ref		Ref
Yes	34	32 (94.1)	3.21 (2.62–3.93)	< 0.001	1.57 (1.19–2.07)	0.001*

Abbreviations: APR, Adjusted prevalence ratio; CPR, Crude prevalence ratio; SFM, superficial foot mycoses.

^* p‐value < 0.05.

Sharing football boots was not significantly associated with SFM in the multivariable analysis. Although the prevalence appeared higher among players who shared boots (APR = 2.06, 95% CI: 1.36–3.12), the association did not reach statistical significance (p = 0.08).

4. Discussion

SFM refers to fungal infection mostly caused by dermatophytes, including onychomycosis and tinea pedis that affect the nail plate and the interdigital space of toes respectively or both. Footballers are at high risk due to a combination of factors. The warm and moist environment created by shoes and socks provides the perfect breeding ground for fungal growth [2]. This study was aimed at investigating the prevalence of superficial, clinical spectrum and factors associated with SFM among professional footballers in a resource limited country. Our study revealed that SFM is a common condition among footballers. Clinically, onychomycosis was more prevalent than tinea pedis, and both may coexist. The main associated factors identified were sharing sports gear, sharing communal bathrooms, toe nail trauma, and family history of mycosis. Similar trends were reported in Brazil, whereby prevalence ranged from 32% to 38.6% [1, 5]. However, higher prevalence rates of 61.1% of onychomycosis and 33.3% of tinea pedis and 60.7% of onychomycosis and 36.9% of tinea pedis were reported in Colombia and Germany, respectively [6, 7]. These findings demonstrated that professional footballers represent a high‐risk group. It might also reflect a possible high level of SFM transmission within the teams and the need to implement preventive measures. The main clinical spectrum of SFM was dominated by onychomycosis found more in males than females, with distal and lateral subungual onychomycosis and total dystrophy onychomycosis as the most common type. Interdigital Tinea pedis was the second most common type of SFM found in Tanzanian Premier League footballers. The high frequency of onychomycosis could be explained either because it is rarely symptomatic which does not prompt footballers to consult. In contrast, tinea pedis is commonly associated with symptoms that might lead footballers to seek for medication. Our study findings is consistent with those of Sabadin et al., who also reported DLSO as the most common form of onychomycosis among footballers [5].

Co‐infections with different organisms and the presence of gram‐negative toe web infections emphasise the clinical complexity and potential impact on footballer's performance because these lead to pain, itching, and interdigital maceration which not only hinder performance but also carry psychosocial burdens, such as reluctance to wear open footwear due to cosmetic concerns. This study found a significant association between sock sharing and the prevalence of SFM; footballers who shared socks had a 42% prevalence of SFM, notably higher than those who do not share socks. These findings highlight the critical role of behavioural and hygiene‐related practices in the transmission of fungal infections within the football environment. Yet it is standard practice among top‐tier Premier League teams for each player to have personalised socks marked with their jersey number, thereby minimising direct sharing; the risk of indirect transmission remains. A study conducted by Buder et al. in Germany reinforces the concern regarding indirect transmission of SFM. It demonstrated that laundering contaminated socks at temperatures below 60°C may fail to effectively eliminate fungal spores, thereby enabling cross‐contamination during the washing process. This highlights the risk of ongoing transmission even in environments where direct sharing of clothing is uncommon. Supporting this, Dagget et al. revealed that in a simulated scenario where contaminated and clean laundry were mixed in a clothes basket for 1 h, approximately 10% of the clean garments became contaminated with Trichophyton rubrum and Candida species, known pathogenic agents in SFM [2, 6].

Considering the physically demanding and high‐contact nature of football played by both male and female athletes, this study established that toenail trauma is significantly associated with a two‐fold increased risk of developing SFM. This finding aligns with observations made by Sabadin et al., who noted that foot trauma disrupts the structural integrity of the nail and foot‐skin, thereby making it more vulnerable to penetration and colonisation by fungal pathogens. Moreover, toenail trauma is worsened by players avoiding insole padding to achieve a tighter, more comfortable fit during training and matches. A compromised nail surface creates a conducive environment for dermatophytes and other opportunistic fungi to thrive, facilitating the onset and persistence of infection [5, 8]. This study revealed a statistically significant association between the use of communal showers in team bathing facilities (showering in club changing room) and the occurrence of SFM among footballers (p = 0.007). Similar findings were observed in a Brazilian study involving visiting Chinese teams, where Araújo et al. highlighted that the persistently high levels of contamination in shared bathing environments cannot be effectively reduced unless infected individuals are successfully treated. Additionally, Caputa et al. reported the isolation of fungal pathogens from public bathrooms in athletic camps, further emphasising the critical role of shared hygiene facilities in the transmission of fungal infections [3, 5, 9].

The study further identified that footballers originating from households or family members with a history of SFM had a 57% higher risk of contracting the infection, highlighting the role of environmental and familial exposure in transmission. This observation is supported by findings from Jazdarehee et al., who proposed that fungal transmission within households may occur through the shared use of slippers, or via indirect contact with contaminated surfaces such as carpets or bathroom floors previously used by infected individuals carrying viable fungal arthrospores [10]. A study in Argentina and France found that T. rubrum ‐related nail infections often co‐occur with sole infections and appear hereditary. At least one parent and often the children showed similar infections confirmed by clinical tests. This suggests a genetic predisposition to fungal susceptibility [11]. Although this study provides valuable local insight, its limitations—including the moderate sensitivity of KOH microscopy and a cross‐sectional design—suggest that actual prevalence may be underestimated, and causal relationships should be interpreted with caution.

Overall, this discussion underscores the importance of targeted interventions, including hygiene education, proper gear use, injury prevention, and early screening, tailored specifically to elite footballers. These efforts could mitigate both the dermatological and performance‐related consequences of superficial foot mycoses in this high‐risk population.

Author Contributions

Kamilya Mzee: data curation, investigation, methodology. Angela Mushi: investigation, methodology, data curation. Mike Mboneko: data curation, methodology, investigation, project administration. Millcent M. Nyange: investigation, methodology, data curation. Rune Nathaniel Philemon: conceptualization, writing – original draft, writing – review and editing, supervision. Erick Kitira: formal analysis, software, methodology. Alya Said: data curation, investigation, methodology. Andrew Mhando: conceptualization, investigation, writing – original draft, methodology, visualization, writing – review and editing, formal analysis, project administration, software, data curation, resources, validation, funding acquisition, supervision. Ousmane Faye: writing – original draft, writing – review and editing, supervision, formal analysis. Roderick Hay: writing – review and editing, supervision. Charles Muiruri: conceptualization, supervision. Daudi Mavura: supervision, conceptualization, methodology, formal analysis, project administration, writing – review and editing, writing – original draft, investigation, visualization.

Conflicts of Interest

The authors declare no conflicts of interest.

Data Availability Statement

The data that support the findings of this study are openly available in Github at https://docs.github.com/en/repositories/creating‐and‐managing‐repositories/cloning‐a‐repository.