Athlete's foot
Abstract
Introduction
Around 15% to 25% of people are likely to have athlete's foot at any one time. The infection can spread to other parts of the body and to other people.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical question: What are the effects of topical treatments for athlete's foot? We searched: Medline, Embase, The Cochrane Library, and other important databases up to July 2008 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
Results
We found 14 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
Conclusions
In this systematic review we present information relating to the effectiveness and safety of the following interventions: improved foot hygiene, including socks and hosiery; topical allylamines (naftifine and terbinafine); topical azoles (bifonazole, clotrimazole, econazole nitrate, miconazole nitrate, sulconazole nitrate, and tioconazole); and topical ciclopirox olamine.
Key Points
Fungal infection of the feet can cause white and soggy skin between the toes, dry and flaky soles, or reddening and blistering of the skin all over the foot.
- Around 15% to 25% of people are likely to have athlete's foot at any one time.
- The infection can spread to other parts of the body and to other people.
Topical allylamines (naftifine and terbinafine), topical azoles (clotrimazole, miconazole nitrate, tioconazole, sulconazole nitrate, bifonazole, and econazole nitrate) and topical ciclopirox olamine are all more likely to cure fungal skin infections compared with placebo.
- Topical allylamines seem to have fewer treatment failures compared with topical azoles.
- We don't know if any one treatment is more effective than others.
We don't know whether improving foot hygiene or changing footwear can help to cure athlete's foot.
About this condition
Definition
Athlete's foot is a cutaneous fungal infection caused by dermatophyte infection. It is characterised by itching, flaking, and fissuring of the skin. It may manifest in three ways: the skin between the toes may appear macerated (white) and soggy; the soles of the feet may become dry and scaly; and the skin all over the foot may become red, and vesicular eruptions may appear. It is conventional in dermatology to refer to fungal skin infections as superficial in order to distinguish them from systemic fungal infections.
Incidence/ Prevalence
Epidemiological studies have produced various estimates of the prevalence of athlete's foot. Studies are usually conducted in populations of people who attend dermatology clinics, sports centres, or swimming pools, or who are in the military. UK estimates suggest that athlete's foot is present in about 15% of the general population. Studies conducted in dermatology clinics found prevalences of 25% in Italy (722 people) and 27% in China (1014 people). A population-based study conducted in 1148 children in Israel found the prevalence among children to be 30%.
Aetiology/ Risk factors
Swimming-pool users and industrial workers may be at increased risk of fungal foot infection. However, one survey identified fungal foot infection in only 9% of swimmers, with the highest prevalence (20%) being in men aged 16 years and older.
Prognosis
Fungal infections of the foot are not life-threatening in people with normal immune status, but in some people they cause persistent itching and, ultimately, fissuring. Some people are apparently unaware of persistent infection. The infection can spread to other parts of the body and to other individuals.
Aims of intervention
To control symptoms and prevent recurrence, with minimal adverse effects.
Outcomes
Mycological cure rates: Rates of fungal eradication, shown by negative microscopy and culture, and resolution of clinical signs and symptoms at follow-up. We have chosen mycological cure as a primary outcome. This is because clinical cure is not reported consistently in superficial mycology trials. The main systematic review identified by Clinical Evidence has expressed the outcome in terms of treatment failure rates. Microscopy and culture results are the most frequently used efficacy outcomes in athlete's foot research. However, like many other diagnostic tests, microscopy and culture are not absolutely accurate.
Methods
Clinical Evidence search and appraisal July 2008. The following databases were used to identify studies for this systematic review: Medline 1966 to July 2008, Embase 1980 to July 2008, and The Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Clinical Trials 2008, Issue 2 (1966 to date of issue). An additional search was carried out of the NHS Centre for Reviews and Dissemination (CRD) — for Database of Abstracts of Reviews of Effects (DARE) and Health Technology Assessment (HTA). We also searched for retractions of studies included in the review. Abstracts of the studies retrieved from the initial search were assessed by an information specialist. Selected studies were then sent to the contributor for additional assessment, using pre-determined criteria to identify relevant studies. Study design criteria for inclusion in this review were: published systematic reviews and RCTs in any language, at least single blinded, and containing more than 20 individuals. Trials with any loss to follow-up were sent and there was no minimum length of follow-up required to include studies. We excluded all studies described as “open”, “open label”, or not blinded unless blinding was impossible. Where potentially relevant non-English language references were identified by searches, these have been translated and appraised for inclusion. Studies were not excluded based on high withdrawal rates, as this is a common problem for studies of athlete's foot. We included systematic reviews of RCTs, and RCTs where harms of an included intervention were studied applying the same study design criteria for inclusion as we did for benefits. In addition, we use a regular surveillance protocol to capture harms alerts from organisations such as the FDA and the UK Medicines and Healthcare products Regulatory Agency (MHRA), which are added to the reviews as required. To aid readability of the numerical data in our reviews, we round many percentages to the nearest whole number. Readers should be aware of this when relating percentages to summary statistics such as relative risks (RRs) and odds ratios (ORs). We have performed a GRADE evaluation of the quality of evidence for interventions included in this review (see table). The categorisation of the quality of the evidence (high, moderate, low, or very low) reflects the quality of evidence available for our chosen outcomes in our defined populations of interest. These categorisations are not necessarily a reflection of the overall methodological quality of any individual study, because the Clinical Evidence population and outcome of choice may represent only a small subset of the total outcomes reported, and population included, in any individual trial. For further details of how we perform the GRADE evaluation and the scoring system we use, please see our website (www.clinicalevidence.com).
Table
GRADE Evaluation of interventions for Athlete's foot.
| Important outcomes | Adverse effects, Mycological cure rates | ||||||||
| Studies (Participants) | Outcome | Comparison | Type of evidence | Quality | Consistency | Directness | Effect size | GRADE | Comment |
| What are the effects of topical treatments for athlete's foot? | |||||||||
| 13 (1524) | Mycological cure rates | Topical allylamines versus placebo | 4 | 0 | –1 | 0 | 0 | Moderate | Consistency point deducted for heterogeneity among RCTs |
| 1 (68) | Mycological cure rates | Topical allylamines versus each other | 4 | –1 | 0 | 0 | 0 | Moderate | Quality point deducted for sparse data |
| 15 (2042) | Mycological cure rates | Topical allylamines versus topical azoles | 4 | 0 | –1 | 0 | 0 | Moderate | Consistency point deducted for heterogeneity among RCTs |
| 13 (1259) | Mycological cure rates | Topical azoles versus placebo | 4 | 0 | –1 | 0 | 0 | Moderate | Consistency point deducted for conflicting results |
| 9 (1287) | Mycological cure rates | Topical azoles versus each other | 4 | 0 | –1 | 0 | 0 | Moderate | Consistency point deducted for conflicting results |
| 1 (87) | Mycological cure rates | Topical azoles versus ciclopirox olamine | 4 | –1 | 0 | 0 | 0 | Moderate | Quality point deducted for sparse data |
| 3 (618) | Mycological cure rates | Topical ciclopirox olamine versus placebo | 4 | 0 | –1 | 0 | 0 | Moderate | Consistency point deducted for heterogeneity among RCTs |
We initially allocate 4 points to evidence from RCTs, and 2 points to evidence from observational studies. To attain the final GRADE score for a given comparison, points are deducted or added from this initial score based on preset criteria relating to the categories of quality, directness, consistency, and effect size. Quality: based on issues affecting methodological rigour (e.g., incomplete reporting of results, quasi-randomisation, sparse data [<200 people in the analysis]). Consistency: based on similarity of results across studies. Directness: based on generalisability of population or outcomes. Effect size: based on magnitude of effect as measured by statistics such as relative risk, odds ratio, or hazard ratio.
Glossary
| Moderate-quality evidence | Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. |
Notes
Disclaimer
The information contained in this publication is intended for medical professionals. Categories presented in Clinical Evidence indicate a judgement about the strength of the evidence available to our contributors prior to publication and the relevant importance of benefit and harms. We rely on our contributors to confirm the accuracy of the information presented and to adhere to describe accepted practices. Readers should be aware that professionals in the field may have different opinions. Because of this and regular advances in medical research we strongly recommend that readers' independently verify specified treatments and drugs including manufacturers' guidance. Also, the categories do not indicate whether a particular treatment is generally appropriate or whether it is suitable for a particular individual. Ultimately it is the readers' responsibility to make their own professional judgements, so to appropriately advise and treat their patients.To the fullest extent permitted by law, BMJ Publishing Group Limited and its editors are not responsible for any losses, injury or damage caused to any person or property (including under contract, by negligence, products liability or otherwise) whether they be direct or indirect, special, incidental or consequential, resulting from the application of the information in this publication.
References
Naftifine, terbinafine (topical allylamines)
Summary
Topical allylamines (naftifine and terbinafine) are all more likely to cure fungal skin infections compared with placebo.
Topical allylamines seem to have fewer treatment failures compared with topical azoles .
We found no clinically important results from RCTs about topical allylamines compared with topical ciclopirox olamine in people with athlete's foot.
Benefits and harms
Topical allylamines versus placebo:
We found one systematic review (search date 2005) and two subsequent RCTs assessing the effects of topical allylamines in athlete's foot.
Mycological cure rates
Topical allylamines compared with placebo Topical allylamines used for between 1 and 4 weeks are more effective at curing athlete's foot (defined as negative results on microscopy and no growth of dermatophytes in culture) at 2 to 6 weeks (moderate-quality evidence).
Adverse effects
Topical allylamines versus each other:
The review identified one RCT (62 people) comparing naftifine versus terbinafine. The review found no significant difference in treatment failure between naftifine and terbinafine at 2 and 6 weeks.
Mycological cure rates
Naftifine and terbinafine compared with each other Naftifine and terbinafine seem to be equally effective at curing athlete's foot (defined as negative results on microscopy and no growth of dermatophytes in culture) at 2 to 6 weeks (moderate-quality evidence).
Topical allylamines versus topical azoles:
The review assessed treatment failure for short-term, medium-term, and long-term outcomes.
Mycological cure rates
Topical allylamines compared with topical azoles Topical allylamines and topical azoles seem equally effective at curing athlete's foot (defined as negative results on microscopy and no growth of dermatophytes in culture) (moderate-quality evidence).
Topical allylamines versus topical ciclopirox:
We found no RCTs.
Further information on studies
The review reported that there was significant statistical heterogeneity among RCTs included in the meta-analyses of all interventions at all time points (review set statistical heterogeneity as significant if P <0.05). The clinical heterogeneity among the RCTs included in the meta-analysis in language, healthcare systems, dosage, duration of treatment, and study quality may have led to the significant statistical heterogeneity reported by the review.
The systematic review included men and women of any age with a fungal infection of the skin of the foot identified by microscopy and growth of dermatophytes in culture. It calculated treatment failure rates from reported mycological results. Treatment success was defined as negative results on microscopy and no growth of dermatophytes in culture. The review excluded RCTs that did not subject skin samples to potassium hydroxide and culture. It reported outcomes at three different time points: short (2 weeks), medium (6 weeks), and long term (12 weeks or above).
Comment
None.
Substantive changes
Topical allylamines (naftifine, terbinafine): One already reported systematic review updated and two RCTs added. The updated review confirmed previous conclusions, and found that naftifine and terbinafine were more effective at curing athlete's foot (defined as negative results on microscopy and no growth of dermatophytes in culture) compared with placebo, but not significantly different compared with each other. It found that the results for cure rates between allylamines and azoles were inconclusive. The RCTs found that topical allylamines were more effective than placebo at curing fungal skin infections. Categorisation unchanged (Beneficial).
Azoles (topical)
Summary
Topical azoles (clotrimazole, miconazole nitrate, tioconazole, sulconazole nitrate, bifonazole, and econazole nitrate) are all more likely to cure fungal skin infections compared with placebo.
Benefits and harms
Topical azoles versus placebo:
We found one systematic review (search date 2005), assessing the effects of topical azoles in athlete's foot.
Mycological cure rates
Topical azole creams compared with placebo Topical azole creams used for 4 to 6 weeks are more effective at curing athlete's foot (defined as negative results on microscopy and no growth of dermatophytes in culture) at 2 and 6 weeks (moderate-quality evidence).
Topical azoles versus each other:
The review identified nine RCTs (1287 people) comparing different azoles versus each other and reported short-term (2 weeks) and medium-term (6 weeks) outcomes.
Mycological cure rates
Topical azoles compared with each other Bifonazole, clotrimazole, econazole, miconazole, tioconazole, and sulconazole seem equally effective at curing athlete's foot (defined as negative results on microscopy and no growth of dermatophytes in culture) at 2 and 6 weeks (moderate-quality evidence).
Topical azoles versus topical allylamines:
See options on topical allylamines.
Topical azoles versus ciclopirox olamine:
The systematic review identified one RCT.
Mycological cure rates
Clotrimazole compared with ciclopirox olamine Clotrimazole and ciclopirox olamine seem equally effective at curing athlete's foot (defined as negative results on microscopy and no growth of dermatophytes in culture) at 2 weeks and 4 to 6 weeks (moderate-quality evidence).
Further information on studies
None.
Comment
None.
Substantive changes
Topical azoles: One already reported systematic review updated, which confirmed previous conclusions. The updated review found that azole preparations were more effective at 4 to 6 weeks at curing athlete's foot (defined as negative results on microscopy and no growth of dermatophytes in culture) compared with placebo. It found that the results for cure rates between allylamines and azoles were inconclusive. The review found insufficient evidence of a difference in cure rates between different azoles at 2 to 6 weeks. It also found no significant difference in cure rates between clotrimazole and ciclopirox olamine. Categorisation unchanged (Beneficial).
Ciclopirox olamine (topical)
Summary
Topical ciclopirox olamine is more likely to cure fungal skin infections compared with placebo.
We found no clinically important results from RCTs about ciclopirox olamine compared with topical allylamines in people with athlete's foot.
Benefits and harms
Topical ciclopirox olamine versus placebo:
We found one systematic review (search date 2005; 2 RCTs, 485 people), and one additional RCT comparing ciclopirox olamine versus placebo.
Mycological cure rates
Compared with placebo Topical ciclopirox olamine (0.77% or 1%) is more effective at curing athlete's foot (defined as negative results on microscopy and no growth of dermatophytes in culture) at 2 and 6 weeks (moderate-quality evidence).
Adverse effects
Topical ciclopirox olamine versus topical azoles:
See options on topical azoles.
Topical ciclopirox olamine versus topical allylamines:
See options on topical allylamines.
Further information on studies
The review gave no information on adverse effects associated with ciclopirox olamine. However, the RCTs included in the review reported burning, stinging, and itching sensations (no further details reported).
Comment
None.
Substantive changes
Topical ciclopirox olamine: One already reported systematic review updated, which confirmed previous conclusions. It found that ciclopirox olamine was more effective at curing athlete's foot (defined as negative results on microscopy and no growth of dermatophytes in culture) at 2 and 4 weeks compared with placebo, but found no significant difference between clotrimazole and ciclopirox olamine. Categorisation unchanged (Beneficial).
Socks, stockings, foot hygiene
Summary
We don't know whether improving foot hygiene or changing footwear can help to cure athlete's foot.
Benefits and harms
Socks, stocking, foot hygiene:
We found no direct information from RCTs on the effects of foot hygiene and hosiery in the treatment of athlete's foot.
Further information on studies
None.
Comment
Evidence from the placebo arms of RCTs suggests that improved foot hygiene can achieve mycological cure in some people.
Substantive changes
No new evidence