Tinea pedis ( Athlete’s foot )
Fungal infection of the feet are a common problem and includes tinea pedis ( also known as athlete’s foot ) and tinea unguinum. This chart here is focused on tinea pedis ( TP )
Tinea pedis ( Athlete’s foot ) – three variants are recognized interdigital plantar ( moccasin ) vesicobullous
Interdigital – most common maceration and fissuring of the skin between the toes
Plantar or mocassin – hyperkeratosis and squamous plaques which cover the soles , heels and the side of the foot
Inflammatory condition may present with vesicles , pustules and sometimes bullae normally on instep or plantar surfaces of the feet
Very common -athlete’s foot is the most common dermatophyte infection Estimated to be the second most common skin disease in the US behind acne Up to 20% to 25 % of the world population may be affected ( Havlickova 2008 ) Rippon ( 1998 ) reported that 70 % of the world population is infected with athlete’s foot at some point of their life Considered a global health problem due to its contagious and recurrent nature.
Caused by dermatophytes Mostly by Trichophyton rubrum ( more than 70 % of cases ) Others Trichophyton interdigitale , Epidermophyton floccosum ,Trichosporum violaceum
Fungus release enzyme keratinase which invades the keratin layer of the skin Keratinocytes constitute a physical barrier and play a role in cutaneous immune reactions and are also known to release antimicrobial peptides including defensins , cathelicidins and psoriasin Molecules called mannans can lower the body’s immunity High temp , an alkaline pH and hyperhidrosis facilitate pedal infection Host factor which predispose to these infections include broken skin , maceration of the skin and immunosuppression.
Seen more commonly in males Survives in warm moist areas Infection is contagious and infected individual shed spores – for eg on the floor of swimming pool facilities , locker rooms , showers etc Direct contact with causative organisms , barefoot walking can lead to infection It can survive in shoes ( for e.g tight shoes where air cannot circulate – heavy industrial boots ) Can be spread from one site of the body to another Risk factors include ○ diabetes or other conditions associated with immunodeficiency as HIV , organ transplant , chemotherapy , steroids ○ hot and humid environment ○ occlusive footwear worn for long durations ○ hyperhidrosis ( excessive sweating ) ○ prolonged exposure to water ○ use of public baths , showers , changing areas ○ poor peripheral circulation ○ age – prevalence generally increases with age 25-44 yrs ( seen rarely in children ) ○ family h/o fungal infection of the foot ○ marathon runners ( and contact sports ) ○ certain occupations as miners , soldiers ○ people living in institutions and long term care
Interdigital type tinea pedis
most commonly in interspace of the 4th and 5th digits itching and burning sensation , malodor affects dorsal surface of the foot but adjacent plantar areas can also be involved two presentations are recognised dermatophytosis simplex presents with skin which is dry and with low grade peeling -may just cause occasional itching and is usually asymptomatic dermatophytosis complex – may present with fissuring of the interspace with hyperkeratosis , leukokeratosis or erosions a break in cutaneous integrity may predispose to bacterial infection.
more severe and prolonged form covers the lateral aspect of the foot in in a shipper or moccasin distribution skin of the affected parts is often scaly and hyperkeratotic with erythema can often be bilateral T rubrum is the most common pathogen other conditions to consider include psoriasis , syshidrotic , atopic or allergic eczematous dermatitis , pitted keratolysis and various keratodermas.
Vesiculobullous tinea pedis less common bacterial infection should be ruled out by microscopy or culture other conditions to consider include bullous impetigo , allergic contact dermatitis, dyshidrotic eczema , bullous disease
History and examination in most cases are adequate to establish a working diagnosis Microscopy and culture of skin scrapings can confirm the diagnosis Obtain dry scales from the instep , heel , and sides of the foot Direct microscopy of a KOH preparation ( added to the glass slide ) Cultures and histological examinations are rarely needed.
educate about predisposing factors and the possibility of chronicity adequate foot hygiene proper footwear which keeps the foot cool and dry cotton socks changed every day frequent changing of shoes ( e.g every 2-3 days ) dry the feet well after washing particularly between the toes avoid barefoot walking in public areas ( e.g swimming pools ) avoid sharing towels , socks , slippers , shoes and towels avoid scratching affected areas to prevent spreading the infection.
Mainstay of treatment are topical antifungal preparations Eradication may take up to 2-6 weeks Always advice to continue treatment for 1 week after the disappearance of all signs of infection Application area should include normal skin about 2 cm beyond the affected area Use creams in all areas and ointments in dry areas First line treatments include ( RCTs have not shown any difference in antifungal effects , safety , tolerability among different antifungal classes ) imidazoles ( clotrimazole e, g Canesten® ) ketoconazole ( Daktarin Gold® ) miconazole ( Daktarin Aktiv® ) terbinafine ( Lamisil® ) Topical terbinafin and amorolfine can produce a faster response in comparison to clotrimazole Reinfection is possible Magenta paint ( Castellani’s paint ) is also used in some cases of inflammatory tinea pedis with bacterial coinfection Antifungal dusting powders may cause skin irritation but can be used in shoes and socks to prevent re-infection Combining antifungal agent with topical corticosteroids provides symptomatic relief
Systemic therapy- For patients who have failed to respond to topical agents Recurrent infection or has blisters Patients with extensive chronic hyperkeratotic TP or inflammatory and vesicular TP Can be used 1st line in severe disease or if the patient is Immunocompromised , has diabetes or peripheral vascular disease Azoles which include ketoconazole , itraconazole and fluconazole are often used as 1st line agents in the UK , please refer to BNF regarding indications , usage and adverse effects Terbinafine @ 250 mg /day is known to provide rapid and long lasting remission
Complications – Subsequent toe nail infection ( tinea unguum ) Bacterial infection- cellulitis Spread to other parts of body Pyoderma , lymphangitis , Osteomyelitis Persistent infection can cause fissuring between the toes Dermatophytes and Majocchi’s granuloma ( also refereed to as ID reaction – it is an immunological reaction secondary to tinea pedis along with other tinea infections ) Asthma and atopic disease
In patients with lymphedema presence of tenia pedis is a risk factor for cellulitis
Advice to see GP if symptoms not resolving within 7 days If you suspect an alternative condition as ○ eczema / psoriasis ○ diabetes ( check BM if possible ) ○ candidiasis ○ bacterial infection ( cellulitis ) ○ patient is immunosuppressed and the infection is generalised ○ toe nails are black or discolored Condition is recurring Infection is severe and extensive
PATIENT INFORMATION LINKS
An excellent review with pictures for the patient from HSE Ireland https://www2.hse.ie/conditions/athletes-foot.html
Boot’s athlete foot cream PIL is useful -from medicine compendium https://www.medicines.org.uk/emc/product/8277/pil#gref
Royal College of Podiatry on athletes foot with a self-referral section – when to see a podiatrist https://cop.org.uk/common-foot-problems/athletes-foot
Printable 2 page guidance https://dphhs.mt.gov/Portals/85/dsd/documents/DDP/MedicalDirector/AthletesFoot.pdf
Self care information about athletes foot from Walsall Clinical Commissioning Group https://walsallccg.nhs.uk/stay-well-walsall/self-care/self-care-button-board/athletes-foot-self-care-information/
Printable 4 page information leaflet from Rotherham Doncaster and South Humber NHS https://www.rdash.nhs.uk/wp-content/uploads/2014/02/Athletes-foot-leaflet.pdf
- Toukabri, Nourchène et al. “Prevalence, Etiology, and Risk Factors of Tinea Pedis and Tinea Unguium in Tunisia.” The Canadian journal of infectious diseases & medical microbiology = Journal canadien des maladies infectieuses et de la microbiologie medicale vol. 2017 (2017): 6835725. doi:10.1155/2017/6835725
- Nigam PK, Saleh D. Tinea Pedis. [Updated 2020 Sep 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK470421/
- Dermnetz Tinea pedis https://dermnetnz.org/topics/tinea-pedis/
- Gupta, Aditya K et al. “Topical treatments for athlete’s foot.” The Cochrane Database of Systematic Reviews vol. 2018,1 CD010863. 24 Jan. 2018, doi:10.1002/14651858.CD010863.pub2
- Al Hasan, Muhannad et al. “Dermatology for the practicing allergist: Tinea pedis and its complications.” Clinical and molecular allergy : CMA vol. 2,1 5. 29 Mar. 2004, doi:10.1186/1476-7961-2-5
- Best Practice Guideline Athlete’s foot https://dphhs.mt.gov/Portals/85/dsd/documents/DDP/MedicalDirector/AthletesFoot.pdf
- Sahoo, Alok Kumar, and Rahul Mahajan. “Management of tinea corporis, tinea cruris, and tinea pedis: A comprehensive review.” Indian dermatology online journal vol. 7,2 (2016): 77-86. doi:10.4103/2229-5178.178099
- Ilkit M, Durdu M. Tinea pedis: the etiology and global epidemiology of a common fungal infection. Crit Rev Microbiol. 2015;41(3):374-88. doi: 10.3109/1040841X.2013.856853. Epub 2014 Feb 4. PMID: 24495093.