Tinea Corporis Infection - Guidelines for Prescribing Topical Antifungals

Description of tinea corporis (ringworm)
  • 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 and up to 44% of wrestlers (known as tinea corporis gladiatorum). 
  • Men are more often affected than women.
  • 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.
  • Tinea infection is classified by location 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.

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

Signs and Symptoms
  • Begins as a small round, red spot on face, neck, trunk or limbs.  Usually on smooth, hairless areas.
  • Gradually expands outward in a circular fashion with a raised, scaly erythematous border and a clear central area.
  • Lesions may be from 1 to 10 cm in circumference.
  • Itchiness and burning sensation are common, but may be asymptomatic.
  • Outbreaks common in close-contact sports
Differential Assessment

Rule out the following conditions which can resemble tinea corporis. With the exception of seborrheic dematitis, these conditions do not respond to topical antifungal treatment.

  • Bacterial infections such as impetigo - pustules with honey-colored crusts or fluid-filled blisters. 
  • 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.  Can have diffuse inflammation and ill-defined borders.
  • Nummular (discoid) eczema - appears as small round plaques of small papules and blisters, usually on arms, neck and legs.  Very itchy, can may persist for months.
  • Psoriasis - presents as red spots covered with thick silver scales, with no central clearing. Refer to physician.
  • Pityriasis rosea - is a viral rash that lasts 6 to 12 weeks, beginning with a "herald" patch: a small, scaly, pink-coloured lesion on the trunk. It starts as a single patch which may be mistaken for tinea corporis. Often preceded by an upper respiratory tract infection.  Self-limiting condition.
  • Allergic contact dermatitis - itchy rash caused by reaction to a substance  that has come in contact with the skin, usually confined to the area exposed to the allergen. 
  • Lichen Simplex - an area of thickened skin with small bumps and/or scaling caused by chronic rubbing or scratching due to itchiness. Does not respond to antifungals. Refer to physician.
  • Lupus erythematosus - may present as an itchy or painful rash most commonly on face but can also occur on the chest and back. Refer to physician
  • Lyme disease - may resemble ringworm without scales at the site of a tick bite. It has a typical bull's-eye appearance starting around the bite and spreading outward. Refer to physician.
  • Tinea capitis - infection of the scalp involving skin surrounding the hair shaft. It is most common in children and if left untreated, can cause scarring and permanent hair loss. Topical treatment does not work; systemic antifungals are required. Refer to physician.
  • Tinea incognito - occurs when a fungal infection is inappropriately treated with steroids, causing the lesion to become less grouped, and the scaly border vanishes.
When to Refer

Most patients with typical signs and symptoms of tinea corporis (ringworm) do not require further investigation, however a physician assessment should be recommended in the following situations:

  • If the lesions are:
    • Extensive (circumference > 10 cm and / or multiple lesions).
    • Severely inflamed
    • Weeping or purulent
    • Painful
    • Disabling
    • On the scalp
  • No improvement after 1 week of pharmacologic treatment.  Refer for an evaluation.
  • Previous tinea infection which did not fully resolve, despite appropriate treatment. Refer for evaluation and possible systemic treatment.
  • 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 self-diagnosis of tinea corporis - requires further evaluation and /or physician-supervised treatment (see Differential Diagnosis above).
Treatment

1. Non-pharmacologic 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.
  • Have pets examined by a veterinarian to make sure that they are not carrying a fungal infection. Be sure to have the animal treated if it is a carrier.
  • 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 organism.

2. Over-the-counter drug options

  • 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 before application 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 cream 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 a longer duration of treatment than 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 via interference 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 7 days. Two weeks of treatment provide slightly better results than one week but may not be clinically significant.
    • Symptoms may 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. Avoid contact between infant and treated skin area as safety of terbinafine 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 through interference with fungal sterol biosynthesis.
    • Dosage: Children and Adults: Apply to clean, dry affected area and surrounding area (approximately 2cm beyond visible edge of lesions) ONCE or TWICE daily; duration of treatment 3 - 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. Clotrimazole and miconazole are the agents of choice in pregnancy but application to large areas should be avoided.
    • 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 for tinea infections.

Advice / Monitoring
  • Discuss and recommend appropriate non-pharmacologic measures.
  • Improvement of symptoms such as itching and burning should occur within a few days, and the infection is not contagious after 24 hours of treatment.
    • Although a person should no longer be contagious 24 hours following the initiation of treatment, the patient should be instructed to avoid direct skin contact with others and sharing clothing or personal items, and restrict activities such as wrestling or swimming.
  • Continue treatment for 1 week after symptoms disappear (except with terbinafine).
  • If symptoms worsen, contact pharmacist or physician.

Assess Benefit

  • Follow-up in 7 days to assess initial effect.
  • Refer to physician 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 does not usually require discontinuation.
  • If symptoms persist or are severe, may indicate contact dermatitis reaction to components of cream. Advise patient to stop therapy and refer to physician.
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 continuing use for 1 week 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, including one week after symptom resolution, up to a maximum of 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 corporis.
    • 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 corporis 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 & Nutrition.
 Sponsored by the Saskatchewan College of Pharmacists.
Posted May 2010. Updated March 2016.