Cutaneous Fungal Infections Athlete's Foot

Transmission of Tinea Pedis

-Directly via contact with infected person -Indirectly - contaminated surfaces of warm moist environments (e.g. swimming pools/decks, change rooms)

Clinical Presentation of Tinea Pedis

• Chronic interdigital infection ‐ Scaling, fissured, whitened, thickened -Often between 4th and 5th toes -May have symptoms of burning and itching or malodour

Overview 1

• Dermatophytoses - Superficial mycotic infections of the skin • Tineais the latin word for fungus -precedes the latin name for the body part that is infected (ie corporis= body, pedis = foot) • Dermatophytes survive on dead keratin -do not invade living tissue -e.g. hair, nails and skin

Patient Assessment: Tinea Pedis

• Differential diagnosis: -Contact dermatitis, eczema, psoriasis or bacterial infections • When assessing patient, consider: -Presenting signs and symptoms (?weeping & oozing, involvement of toenail) -Past medical history -History of the present illness ‐ ?risk factors -Patient Age

Tinea Pedis and Corticosteroids

• Generally recommended to avoid combination therapy products with antifungal agent and corticosteroid • Corticosteroids may help reduce initial inflammation but can lead to treatment failure; long term use can cause unacceptable adverse effects

Tinea Pedis: Application and Duration of Treatment

• Apply to clean dry area -Affected area including 2‐3 cm beyond the border -Most products applied twice daily for 2‐4 weeks (including 1 to 2 weeks after the lesion has cleared) • Refer if no improvement after 2 weeks of treatment

Prevention of Tinea Pedis

• Change socks daily (more frequently if feet are sweaty) • Wash feet with non‐irritating cleansers • Allow shoes to dry completely • Dry feet thoroughly (interdigital) • Do not go barefoot in public facilities • Do not share personal items (flip‐flops) • Wear socks and shoes made from natural material • Absorbent Powder can be used to decrease sweating -Talcum, aluminum chloride

Topical Treatments for Tinea Pedis

• Imidazoles: a) Clotrimazole 1% cream, Twice daily x 2‐4 weeks, OTC b) Miconazole 2% cream, spray, powder, Twice daily x 2‐4 weeks, OTC • Allylamines: Terbinafine 1% cream, spray, Once daily for 1‐2 weeks, Rx Shorter duration of therapy! Miscellan.: a) Tolnaftate 1% cream, gel, aerosol, powder, solution, Twice daily for 2‐4 weeks, OTC b) Ciclopirox 1% cream, lotion, Twice daily for minimum 4 weeks, Rx c) Undecylenic acid ointment, powder,spray (aerosol), Twice daily (up to 4 weeks), OTC

Overview 2

• Most superficial fungal infections caused by: -3 genera of dermatophytes (Trichophyton, Epidermophyton, Microsporum) -Yeast‐like fungi (e.g. Candida) • Transmission: -Direct contact from infected people, fomites, the environment (soil) or animals • Predisposing host factors: -Moisture (occlusive clothing/shoes, warm humid climates) -Genetic susceptibility -Impaired immunity (e.g. diabetes, HIV, chemotherapy)

When to Refer with Tinea Pedis

• Patient has diabetes, cancer, peripheral vascular disease • Patient is immunocompromised • Patient is elderly/malnourished • Patient under the age of 12 • Lesion is oozing, severely inflamed, eczematous • Toenail involved (discoloration) • No improvement seen within 2 weeks or symptoms have not completely disappeared within 6 weeks. • Unable to differentiate tinea infection from eczema, psoriasis or other skin disorders

Tinea Pedis: Pathophysiology

• Several organisms can be involved in causing foot infection: -Most commonly caused by dermatophytes (T. rubrum, T. mentagrophytes, E. flocosum) -Yeast (Candida albicans) can also be involved -Gram‐negative bacteria ‐ulcerative forms • Predisposing risk factors: -Host factors: immunosuppression, poorly controlled diabetes mellitus, obesity, age -Local factors: trauma, occlusive clothing, public showering, moist conditions • Fungus invades outermost layer of skin -Drying and scaling initially (may be asymptomatic) -Moisture and increased temperature by hot sweaty feet promotes fungal growth

Dosage Forms and Applications

• Solution -Allow to completely dry on foot • Lotion -Generally preferred • Cream -Generally preferred • Ointment -Remain in contact the longest however may be occlusive • Powder -Do not apply directly to footwear • Spray -Allow to completely dry on foot

Goals of Therapy

• Symptom relief • Cure infection • Prevent recurrence and transmission

Systemic Therapy for Tinea Pedis

• Terbinafine 250 mg/day x 2 weeks • Itraconazole 200‐400 mg/day x 1 week • Fluconazole 150 mg/week x 2‐6 weeks

Efficacy of Topical Agents for Tinea Pedis

•Allylamines, azoles, tolnaftate, undecanoates all more effective than placebo • Meta‐analysis of 11 trials comparing allylamines and azoles showed a risk ratio of treatment failure [RR 0.63 (95% CI 0.42 to 0.94) in favor of allylamines] • Recurrence is common and treatment failure occurs in ~30% of cases (often due to poor adherence) -Need to assess potential cause of failure

Treatment/Management of Tinea Pedis

•Pharmacological -Topical therapy: Typically used first line -Systemic therapy: consider in patients with diabetes mellitus and immunosuppression; moccasin type presentation (or patients who fail topical therapy) -Not recommended under the age of 2 years, unless directed by physician • Non‐pharmacological -Disease management and preventative -Infection is most commonly transmitted through contact (e.g. swimming pools, gym locker rooms) -Manage hyperhidrosis

Vesicular Tinea Pedis

•Small vesicles near instep and mid‐anterior plantar surface; also typically have skin scaling

Mocassin Type Tinea Pedis

•Typically both feet, mild inflammation and diffuse scaling; toenails may be affected (onychomycosis)

Ulcerative Tinea Pedis

•Weeping and inflammed; often malodour due to secondary bacterial infection