Tinea Cruris Skin Infection - Guidelines for Prescribing Topical Antifungals

Description of tinea cruris infections (jock itch)
  • Fungal or tinea infections of the skin are common, with tinea corporis (ringworm) and tinea cruris (jock itch) affecting 10 to 20% of the general population at some point in their lifetime.
  • Tinea cruris occurs most commonly in adult men and in athletes.
  • Superficial fungal infections of the skin are caused by three dermatophytes; Trichophyton, Epidermophyton and Microsporum which use the keratin layer of the epidermis as their source of nutrition.
  • The type of tinea infection is classified by where it is located on the body, not by the causative organism.
  • Tinea infections are contagious and are spread by skin-to-skin contact with infected humans or animals (most commonly dogs, cats, guinea pigs, horses), by contact with surfaces that have been in contact with infected humans or animals and less often by prolonged contact with dirt that harbours tinea organisms.
  • People with diabetes or who are overweight are more susceptible to tinea cruris.

For more information and photos, go to:
Skinsight.com
DermNet NZ

Signs and Symptoms
  • Presents as large round, red, well-defined patches on the upper inner thight and groin area.
    • Genitals spared
    • Bilateral due to skin-on-skin contact of upper thighs and groin
    • Reddened areas can extend down inner leg or upwards to stomach or buttocks.
  • Edges are bumpy or scaling.
  • Burning and itching are common.
  • Often co-morbid with tinea pedis and tinea unguium (toe-nail infection)

 

Differential Assessment

Rule out the following conditions which can resemble tinea cruris:

  • Candidiasis of skin folds (candida intertrigo) - yeast infection which covers penis and scrotum as well as groin area with diffuse, red papular lesions. This may be treated with OTC antifungals.
  • Seborrheic dermatitis - appears as yellow, greasy, scales on scalp and may extend down to face and upper chest in the form of circular scaly pink patches. In some cases can also affect skinfolds in groin. May respond to self-care treatment. More severe cases should be referred to the patient's primary care provider.
  • Psoriasis - presents as red spots covered with thick silver scales. Does not respond to antifungals. Refer to patient's primary care provider.
  • Erythrasma - a bacterial infection causing slowly enlarging areas of pink or brown scaling skin in folds in the groin, armpits or between the toes. Often asymptomatic. It is bilateral, irregularly shaped, and has scaly plaques.  Treated with topical or systemic antibiotics.
When to Refer

Most patients with typical signs and symptoms of tinea cruris (jock-itch) do not require further investigation, however an assessment by the patient's primary care provider should be recommended in the following situations.

  • If the lesions are:
    • Extensive
    • Severely inflamed
    • Weeping or purulent
    • Painful
    • Disabling
    • On the penis, scrotum or vulva
  • Previous tinea cruris infection did not fully resolve despite appropriate treatment. Refer for evaluation and possible systemic treatment.
  • No improvement after 1 week of pharmacologic treatment. Refer for an evaluation.
  • Patient has diabetes or is immunocompromised due to disease or drug treatment.
  • Patient has symptoms of systemic illness (e.g. fever, fatigue, swollen lymph glands).
  • Unable to confirm patient's diagnosis of tinea cruris. Further evaluation and /or supervised treatment.is required. (See Differential Diagnosis above)
Treatment

1. Non-pharmacological treatment for tinea infections:

  • Skin should be kept dry to help stop infection from spreading.
  • Avoid rubbing or scratching lesions.
  • Use a hair dryer on cool setting to dry the affected area.
  • Wear loose fitting, cotton clothing or moisture absorbing synthetics.
  • Launder items used by infected person separately and often.
  • Use of non-medicated powders may help absorb moisture.  Do not use cornstarch or powders that contain cornstarch as these may provide nourishment for the tinea organisms.
  • The main cause of tinea cruris is transfer of the microorganism from the patient's feet. This can occur while changing after exercise, swimming or bathing.  Instruct patient to fully dry feet and put on socks before undergarments, especially after using a public change room.

2. Over-the-counter drug options for treating tinea infections of the skin

  • OTC anti-fungal agents are available in a variety of dosage forms; creams, lotions, gels, solutions, sprays and powders.  Generally creams and solutions are most effective because they can be massaged into infected areas so more of the product comes in contact with the fungus. Solutions may be easier to apply to hairy areas. Sprays and powders can be useful as adjunctive treatment, especially for oozing lesions and as preventative agents.
    • Tolnaftate 1% available in solution, gel, powder, cream, spray
    • Clotrimazole 1% available in cream
    • Miconazole 2% available in cream, powder spray
  • Directions for application of creams and solutions should include instructions to clean and dry the area and to apply product to visible lesions as well as 2cm to 5cm outside the visible infection. This will help treat fungus which is in the process of spreading. Massage creams into area twice a day for at least 4 weeks. Products should continue to be used for 1 week following resolution to help prevent recurrent infection.
  • OTC anti-fungal treatments have been shown to be effective in treating and curing tinea infections of the skin, but they may require longer duration of treatment than with prescription agents.
  • Pregnancy / Lactation
    • Clotrimazole and miconazole are the agents of choice in pregnancy.
    • In breastfeeding patients, clotrimazole is the drug of choice, but miconazole is acceptable.
    • Tolnaftate has not been thoroughly studied in pregnancy and lactation.

3.  Prescription drug options

Terbinafine 1% Cream and Terbinafine 1% Spray

    • Terbinafine has a broad spectrum of anti-fungal activity. It is fungicidal to dermatophytes by interfering with fungal sterol biosynthesis.
    • Dosage: Children > 12 years old and Adults:  Apply to clean, dry affected area and surrounding area (approximately 2cm beyond visible edge of lesions) ONCE daily for at least 7 days. Two weeks of treatment provided slightly better results than one week but may not be clinically significant.
    •  Symptoms continue to improve for up to 4 weeks after treatment.
    • Less than 5% is absorbed after topical application. Half-life is 27 hours in the stratum corneum.
    • Pregnancy: There are only limited clinical studies so current recommendations are to avoid during pregnancy. However it is not expected to increase the risk of birth defects.    Clotrimazole and miconazole are the agents of choice in pregnancy.
    • Lactation: With topically applied cream and spray treatment, the small amounts absorbed through the skin are unlikely to affect the infant. Terbinafine should not be applied to the breast. Infants should not come into contact with any treated skin area as safety has not been established in children.
    • Pediatrics: Topical terbinafine has not been studied in children <12, so should not be recommended.

Ketoconazole 2% Cream

    • Ketoconazole is fungicidal to tinea dermatophytes by interfering with fungal sterol biosynthesis.
    • Dosage: Apply to clean, dry affected area and surrounding area (approximately 2cm beyond visible edge of lesions) ONCE daily. Duration of treatment: 2 - 4 weeks.
    • Systemic absorption is minimal to undetectable.
    • Treatment should meet, but not exceed recommended duration as safety for longer periods has not been established.
    • Pregnancy: Adverse effects are noted in animal studies with oral ketoconazole. Systemic absorption is very low suggesting that ketoconazole is unlikely to have adverse effects but there is no data to confirm safety. The official recommendation is to avoid during pregnancy. Clotrimazole and miconazole are the agents of choice in pregnancy.
    • Lactation: Has been detected in breast milk at very low concentrations, but since it requires acidic conditions for absorption from the GI tract and alkaline conditions are induced by milk ingestion, significant absorption by breast feeding is unlikely. Rated as probably safe in breastfeeding by the American Academy of Pediatrics.
    • Pediatrics: Can be used in infants and children.

Steroid or combination steroid/anti-fungal products should not be recommended. The itch caused by tinea infections subsides fairly soon after topical antifungal treatment begins. Extended treatment with these products may unnecessarily expose patients to steroid side effects.

Topical nystatin is ineffective.

Advice / Monitoring
  • Discuss and recommend appropriate non-pharmacological measures.
  • Relief of symptoms such as itching and burning should occur within a few days.
  • Continue treatment until and for a 1 week after symptoms disappear, unless using terbinafine.
  • If symptoms worsen, contact pharmacist or patient's primary care provider.

Assess Benefit

  • Follow-up in 7 days to assess initial effect.
  • Refer to patient's primary care provider if:
    • Symptoms not improving
    • New lesions or affected area spreading
    • Pain, swelling or more redness as occured
    • Severe sensitivity to medication
  • If symptoms are improving, advise patient to continue treatment and for 1 week after symptoms disappear (except with terbinafine).

Assess adverse effects

  • Minor redness, itching or stinging do not usually require discontinuation.
  • If symptoms persist or are severe, possible contact dermatitis to components of cream. Advise patient to stop therapy and refer to their primary care provider.

 

Products

Detailed information on contraindications, cautions, adverse effects and interactions is available in individual drug monographs in the CPS (e-CPS), Lexi-Comp, AHFS, www.drugs.com or other reliable drug monograph references. For comprehensive drug comparisons, see RxFiles charts (www.rxfiles.ca).
This information should be routinely consulted before prescribing.

OTC Products

 

Ingredient

Brands

Dosage / Directions

Tolnaftate 1%

Tinactin
Generics


Apply twice daily for four weeks.

Recommend using for two weeks after resolution of symptoms to prevent recurrence

Clotrimazole 1%

Canesten
Generics

Miconazole 2%

Micantin
Monistat
Generics

 

Prescription Products

Ingredient

Brands

DIN

Dosage / Directions

Terbinafine 1% cream

Lamisil cream

02031094

Adults and children >12: 
   Apply once daily for 7 days. 
   Improvements persist for up to
   4 weeks

Terbinafine 1% spray

Lamisil spray

02238703

Ketoconazole 2% cream

Ketoderm

02245662

   Apply once or twice daily for up to one week after symptoms resolve. Maximum duration 4 weeks.

 

 


 
Prescribing and Billing Details
  • pseudoDIN: 00951101
    • Max of 4 claims per 365 days per patient
    • All "tineas" use the same pseudoDIN and thus have a max of 4 claims per 365 days per patient altogether.

  • May prescribe sufficient quantity to treat ONE episode of tinea cruris.
    • Terbinafine: once daily for 7 days only (long duration of action of up to 4 weeks, longer treatment not needed) 
    • Ketoconazole: once or twice daily for 3-4 weeks.  Continue for an additional week after full resolution.
    • For help prescribing the proper quantity of topicals using finger-tip units, see: http://dermnetnz.org/treatments/fingertip-units.html

  • Only products with an official indication from Health Canada for tinea cruris are considered for these guidelines.  Only the active ingredients in the "products" section are approved for pharmacist prescribing.
Treatment Flowchart
Pharmacist Assessment Documents
References / Suggested Reading
  1. Drugs in Pregnancy and Lactation, 6th edition: Gerald G Briggs BPharm, Roger K Freeman MD, Sumner J Yaffe MD By Lippincott Williams & Wilkins Publishers (November 2001) Dynamed Database, Cochrane Database Syst Rev 2014 Aug 4;(8):CD009992
  2. Haaf M. Use of anti-infective agents during lactation, Part 3: Antivirals, antifungals, and urinary antiseptics. Journal of human lactation 2001;17:160-6
  3. Miller P. Dermatological Conditions: Fungal Skin Infections. CTMA. In: RxTx [Internet]. Canadian Pharmacists Association. Available from: http://www.e-therapeutics.ca. (In Saskatchewan available through www.shirp.ca.)
  4. Mallen A. Athlete’s foot. CTMA. In: RxTx [Internet]. Canadian Pharmacists Association. Available from: http://www.e-therapeutics.ca. (In Saskatchewan available through www.shirp.ca.)
  5. Stone S. Antifungal treatment chart. In: RxFiles. Available at www.rxfiles.ca by subscription. (In Saskatchewan available through www.shirp.ca.)
  6. Tinea corporis. In: DynaMed. Available at https://dynamed.ebscohost.com/ by subscription. (In Saskatchewan available through www.shirp.ca.
  7. Goldstein A, Goldstein B. Dermatophyte (tinea) infections. In: UpToDate. Available at www.uptodate.com by subscription.
  8. Fungal skin or nail infections.In: C-Health. chealth.canoe.ca. (Free access)
  9. Ringworm In: Mayo Clinic. www.mayoclinic.org. (Free access)
  10. Ringworm or tinea. In Bluebook – Guidelines for the control of infectious diseases http://ideas.health.vic.gov.au/bluebook/ringworm.asp (Free access)

Prepared by medSask, Your Medication Information Service
Reviewed by Dr. P. Fourie, Family Physician and Dr. Yvonne Shevchuk, Professor, College of Pharmacy and Nutrition.
 Sponsored by the Saskatchewan College of Pharmacy Professionals.
Posted May 2010. Updated May 2017.