Tinea manuum: a 5 year retrospective study of demographic data, clinical characteristics, and treatment outcomes

Abstract

Tinea manuum is a superficial fungal infection affecting the hands, particularly the palms and interdigital areas. This retrospective study investigated clinical features, laboratory findings, treatment, and outcomes in patients with fungal hand infections at Siriraj Hospital between 2016 and 2020. Among 107 patients, representing 1.3% of those with fungal skin infections, 64.5% were male, with a mean age of 54.3 ± 18.5 years. Diabetes mellitus was present in 26.2%, and 23.4% had prior topical steroid use. The most common symptom was itching (75.7%), while palm-scale (85.9%) was the most prevalent clinical finding. Concurrent fingernail onychomycosis was observed in 43%, and 59.8% had additional fungal skin infections. Among 50 positive cultures, dermatophytes accounted for 86% and nondermatophytes for 14%, with Trichophyton rubrum (54%) and Trichophyton mentagrophytes complex (24%) being the most frequent pathogens. Systemic antifungal treatment was administered to 57% of patients, with a mycological cure rate of 56.4%. A complete cure was achieved in 60.5% of dermatophyte infections but in none of the nondermatophyte cases (p = 0.003). These findings highlighted that tinea manuum could be caused by both dermatophytes and nondermatophytes, with significantly poorer outcomes observed in nondermatophyte infections. Concurrent fungal skin and nail infections should be evaluated for optimal management.

Introduction

Superficial fungal infections that affect the hands are a global health concern, with widespread implications for the population at large¹. Fungal hand infections can result from direct contact with infected individuals, animals, or indirectly through exposure to contaminated soil and materials². Among these infections, tinea manuum stands out as a distinct clinical entity characterized by prominent features such as erythema and scaling^3–5. It is important to differentiate tinea manuum from other dermatological conditions, such as dermatitis or eczema, to facilitate accurate diagnosis and targeted treatment. Despite the prevalence of superficial fungal infections, there is a difference in the focus of research, with most studies dedicated to understanding the epidemiology of tinea pedis, while comparatively fewer investigations investigate the nature of the tinea manuum. Previous studies have reported a consistent incidence rate globally; however, the distribution of fungal species and the clinical characteristics of tinea manuum exhibit significant variability across different countries⁶. This divergence is attributed to factors such as geographic location, environmental conditions and cultural practices that evolve over time^3,6–10.

This retrospective study reviewed baseline characteristics, clinical data, treatments, and outcomes in patients with mycologically proven fungal hand infections. Causative agents were reviewed and used for subgroup analysis.

Methods

This retrospective study included patients diagnosed with fungal hand infections from clinical and laboratory confirmation who visited the outpatient unit, Department of Dermatology, Siriraj Hospital Faculty of Medicine, Mahidol University between 2016 and 2020. The authors confirm that the ethical policies of the journal, as noted on the journal’s author guidelines page, have been adhered to and the appropriate ethical review committee approval has been received. This retrospective chart review was authorized by the Siriraj Institutional Review Board (approval number Si 777/2021). Due to the retrospective nature of the study, the Siriraj Institutional Review Board waived the need to obtain informed consent. All methods were performed in accordance with relevant guidelines and regulations.

Routinely, for patients with suspected fungal hand infection, microscopic examination with 20% potassium hydroxide (KOH) preparations from suspected lesions was performed to confirm fungal infection. Patients who were positive for branching septate hyphae on the KOH examination were included in the study, while patients with yeast infection were excluded due to different risk factors and treatment. While fungal cultures were performed upon dermatologists’ decisions. Sabouraud dextrose agar plates, both with and without cycloheximide, were used for fungal culture. The cultures were then kept at a temperature of 27 °C and evaluated every 4 days for 6 weeks. The identification of fungus was made by the consensus of three experienced mycological technicians. For follow-up visits, repeat microscopic examinations of skin lesions were usually performed at intervals of 2 to 4 weeks. Complete cure was defined as the total disappearance of clinical lesions (clinical cure) along with the absence of fungal hyphae on microscopic examination (mycological cure). Baseline characteristics, clinical data, treatments, and patient outcomes were reviewed from medical records. Furthermore, we compared the data of patients infected with dermatophyte and nondermatophyte species.

Statistical analysis

Descriptive statistics (e.g., mean, minimum, maximum, standard deviation, frequency, and percentages) were used to describe baseline characteristics, clinical data, treatments, and outcomes. The inferential statistic was tested according to the distribution of data, independent t test, and rank-sum test for normal and nonnormal distributed data separately. Fisher’s exact test was used for categorical variables. A Kaplan-Meier analysis was applied to determine the median cure time. This study analyzed all statistical data using SPSS Statistics for Windows, version 18 (SPSS Inc., Chicago, IL, USA).

Results

Of the total of 845 patients with superficial fungal skin infection, 107 patients, who underwent a positive microscopic examination for branching septate hyphae of hand lesions, were included in the study with a prevalence of 1.3%. Sixty-nine participants (64.5%) were male, and the mean age of the patients was 54.3 ± 18.5 years. Approximately 30% of fungal hand infection cases were associated with housework and being pet owners. In the cases of palmar involvement, the majority (85.9%) presented with palmar scaling, while 12.1% presented with vesicles. Interdigital areas were involved in only 3 patients (2.8%). Baseline characteristics, clinical characteristics, concurrent fungal infections, treatments, and results are shown in Table 1.

Table 1.

Demographic and clinical finding of patients with Tinea manuum (N = 107).

Demographic data and clinical findings	Total (%) (N = 107)	Number (%)		P-value
		Dermatophyte (N = 43)	Nondermatophyte (N = 7)
Age (years), mean ± SD (min, max)	54.3 ± 18.5 (13, 85)	54.6 ± 17.7 (19, 83)	52.6 ± 18.1 (27, 80)	0.607
Sex
Male	69 (64.5)	28 (65.1)	5 (71.4)	1.000
Comorbidities
Hypertension	37 (34.6)	19 (44.2)	1 (14.3)	0.134
Diabetes mellitus	28 (26.2)	13 (30.2)	1 (14.3)	0.384
Autoimmune disease	5 (4.7)	3 (7.0)	1 (14.3)	0.320
Risk factors
Agriculture	15 (14.0)	4 (9.3)	3 (42.9)	0.051
Bedridden	2 (1.9)	2 (4.9)	0 (0)	0.473
House worker	35 (32.7)	13 (30.2)	3 (42.9)	0.647
Pet	31 (29.0)	18 (41.9)	2 (28.6)	0.530
Previous use of topical steroids	25 (23.4)	10 (23.3%)	1 (14.3)	0.683
Pruritus	81 (75.7)	32 (74.4)	6 (85.7)	0.688
Physical findings of the hand
Interdigital scale	3 (2.8)	1 (2.3)	0 (0)	0.646
Palmar scale	92 (85.9)	32 (74.4)	0 (0)	0.872
Vesiculobullous lesion	13 (12.1)	4 (9.3)	0 (0)	0.458
Other concurrent skin and nail infection a
Fingernail onychomycosis	46 (43.0)	22 (53.7)	4 (57.1)	0.721
Paronychia	11 (10.3)	5 (11.6)	0 (0)	0.646
Tinea faciei	10 (9.3)	5 (11.6)	0 (0)	0.342
Tinea corporis	32 (29.9)	17 (39.5)	1 (14.3)	0.197
Tinea cruris	23 (21.5)	12 (27.9)	1 (14.3)	0.446
Tinea pedis	29 (27.1)	15 (34.9)	3 (42.9)	0.684
Two feet-one hand syndrome	11 (10.3)	5 (11.6)	2 (28.6)	0.077
Treatments
Topical antifungal	107 (100.0)	9 (20.9)	5 (71.4)	–
Combination with oral antifungal	61 (57.0)	35 (81.4)	2 (28.6)	–
Fluconazole	29 (27.1)	18 (41.9)	1 (14.3)	–
Terbinafine	17 (15.9)	11 (25.6)	1 (14.3)	–
Itraconazole	15 (14.0)	6 (14.0)	0 (0)	–
Complete cure (n = 94)	53/94 (56.4)	26/43 (60.5)	0/2 (0)	0.003*

^aA patient may have more than one concurrent fungal infection site.

*Significant difference at P-value less than 0.05.

Regarding concurrent fingernail involvement, 46 (43.0%) cases had onychomycosis and 11 (10.3%) cases had paronychia. Tinea pedis was diagnosed in 29 (27.1%) cases. 11 (10.3%) cases were classified as having one-hand two-feet syndrome.

Fungal culture at the first visit was performed in 102 patients. Causative agents could be identified in 50 patients from fungal culture, while 52 others did not show fungal growth in culture. The majority of causative organisms (43/50, 86%) were dermatophytes, including 27 (54%) cases of Trichophyton rubrum, 12 (24%) cases of T. mentagrophytes complex, 2 (4%) cases of M. canis, 1 (2%) case of T. tonsurans and 1 (2%) case of M. gypseum. The remaining (7/50, 14%) were nondermatophyte, such that 2 (4%) were Neoscytalidium dimidiatum, 2 (4%) were Penicillium spp, and the rest were caused by Aspergillus niger, Cladosporium spp, and Fusarium spp. Baseline characteristics, clinical characteristics, concurrent fungal skin and nail infections, treatments, and outcomes between the dermatophyte and nondermatophyte groups are presented in Table 1.

In terms of treatment, all patients received topical antifungal medication. Systemic antifungal agents were prescribed simultaneously with topical treatment in 61 (57.0%) cases, including 29 cases where fluconazole was prescribed, 17 cases that received terbinafine, and 15 cases that were administered itraconazole.

Among the 94 cases who came for follow-up, 53 (56.4%) patients achieved a state of cure. The median time to cure was 7.6 months (Fig. 1), and no statistically significant differences were observed across the various treatment regimens. Of the 53 cases that reached a cure, 20 received only topical antifungal therapy, while 33 underwent a combination of topical and oral antifungal treatment. However, there were no statistically significant differences associated with cure among the different oral antifungals. Furthermore, this study did not reveal statistically significant differences in demographic data, risk factors, causative pathogens from fungal culture, or treatment regimens associated with cure.

Fig. 1.

Probability of mycological cure. Kaplan–Meier estimates illustrating the probability of achieving mycological cure over time in patients receiving treatment for tinea manuum.

Fig. 2.

Comparison of the proportion of pathogens between studies: A comparison of the distribution of causative dermatophytes in our study with findings from previous studies on tinea manuum.

Of the 94 cases who came to follow up, only 45 had identifiable fungal cultures at baseline, 43 and 2 cases were caused by dermatophytes and nondermatophytes respectively. The dermatophyte group demonstrated a commendable 26 (60.5%) cure rate, while none of the nondermatophyte group experienced a successful outcome in this study (p-value 0.03). Among the cured group, 26 out of 53 cases had identifiable causative pathogens, while the remaining 27 cases, diagnosed with tinea manuum based on clinical findings and microscopic examination, either did not undergo fungal cultures or showed no growth in baseline cultures. One of two nondermatophyte patients who attended the appointment but did not reach a cure state was prescribed a daily dose of 10 mg of prednisolone (0.2 MKD) to treat SLE, while the other did not have any underlying disease. Of the 26 dermatophyte cases that were successfully treated, two were treated exclusively with topical antifungal therapy, while the rest received a combination of topical and oral antifungal medications.

This study identified a total of 11 (10.3%) cases of the two feet-one hand syndrome, with 5 out of 7 cases having positive culture belonging to the dermatophyte group and the remaining 2 out of 7 belonging to the non-dermatophyte group. Among the dermatophyte group, 4 cases of the two feet-one hand syndrome were successfully treated, while none of the cases in the nondermatophyte group achieved a cure.

Discussion

This study reviewed patients with fungal hand infections. Itching was the leading symptom and the palmar scale was an important sign of diagnosis. Other skin and nail infections were common and should raise the awareness of physicians of a holistic approach. The causative agents could be molds of dermatophytes and non-dermatophytes that were related to treatment outcomes. Culture should be done in all patients to predict the outcomes. There were several previous studies on fungal hand infection in various countries. This study reviewed and compared the cases of fungal hand infection between the dermatophyte and nondermatophyte groups by inspecting the baseline characteristics, clinical characteristics, treatments, and outcomes of patients with fungal hand infection with the studies^8,10–12 in Fig. 2. The mean age of the patients in this study was 44.2 years, with most cases predominantly male, similar to previous studies^10–12.

Some underlying diseases, such as diabetes mellitus, hypertension, and poor hygiene conditions, had previously been reported to be important risk factors^13,14, which were similar to this study. Palmar scale was found in all cases of fungal hand infection – both caused by dermatophytes and nondermatophytes. No specific clinical characteristics were indicative of dermatophytic or nondermatophytic infections. The two feet-one hand syndrome could be caused by both dermatophyte and nondermatophyte groups. This study identified a total of 11 (10.3%) cases of the two feet-one hand syndrome caused by dermatophytes and nondermatophytes.

In this study, T. rubrumwas the most common species of causative dermatophytes with a rate of 61.0%, which was comparable to the results reported in USA⁸, Italy¹¹, and China¹⁵, while other previous studies were dominant in T. mentagrophyte^10,12. The comparison of causative agents with the previous studies is shown in Fig. 2. A study by Cai W et al.¹⁵, conducted in the same region as our country, found that M. canis was the second most common dermatophyte after T. rubrum, while our study showed a significantly lower proportion of M. canis. However, direct comparisons with studies from other countries may be affected by many confounding factors, as each study is influenced by variables such as climate, occupation, patient lifestyles, and study periods. A review of previous studies found a high prevalence of T. mentagrophytes and M. canisas important causative dermatophytes in the temperate zone¹².

Among the dermatophyte group, 80% of the cases were successfully treated, whereas none of the cases in the nondermatophyte group achieved a cure. It is worth noting that tinea manuum may be associated with two feet-one hand syndrome, which could potentially extend the duration required for a complete cure, especially in cases involving non-dermatophytes^7,16.

In terms of treatment outcomes, similar to previous studies, dermatophytes demonstrated a higher cure rate than nondermatophytes, a difference that reached statistical significance. All cured cases underwent a combined treatment regimen that included both topical and systemic oral therapy, with an average cure duration of 7.6 ± 15.2 months, and no statistically significant differences in time to cure were observed across the various treatment regimens.

Limitation

As our study was conducted in a single center, our patients may not fully represent the general prevalence and epidemiology of fungal hand infections for the entire population of Thailand. Furthermore, due to the retrospective nature of the study, some data were unavailable, and complete avoidance of bias was not possible. The absence of statistically significant differences between the dermatophytes and nondermatophytes groups may be attributed to the relatively small sample size.

Conclusions

Tinea mannum commonly presents with scaling and is a significant symptom of pruritus. Dermatophytes are the predominant cause of tinea mannum. Topical therapy with a combination of oral antifungal drugs is recommended in severe or complicated cases. Tinea mannum caused by dermatophytes has a better prognosis than nondermatophytes.

Author contributions

All authors contributed significantly to the work presented in this manuscript. P.S., C.L., P.J. and S.B. conceptualized the study design, conducted data analysis, and drafted the initial manuscript. L.M., W.P., C.P. and A.P. collected patient data, performed laboratory assessments, and contributed to the interpretation of the results. P.S. and C.L. wrote the main manuscript. P.S. and P.J. prepared Figs. 1 and 2. C.L. and S.B. supervised the research, provided critical revisions, and guided the study methodology. All authors reviewed and approved the final version of the manuscript for submission.

Funding

This research did not receive specific grants from funding agencies in the public, commercial, or not-for-profit sectors.

Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Declarations

Ethical approval

The authors confirm that the ethical policies of the journal, as noted on the journal’s author guidelines page, have been adhered to and the appropriate ethical review committee approval has been received. This retrospective chart review was authorized by the Siriraj Institutional Review Board (approval number Si 777/2021).

Competing interests

The authors declare no competing interests.