A 52-year-old homeless man comes to the urgent care clinic due to itching and discomfort in both feet. He has had these symptoms for the past year but they intensified recently. His shoes are uncomfortable and cause irritation. Several shelter residents also have some "swelling of the feet." The patient was told that he has "borderline" diabetes and high blood pressure. He has no regular medical follow-up. Physical examination shows extensive erythema and scaling, especially between the toes, as well as multiple thickened and brittle toenails as shown in the image below.
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Which of the following is the best treatment for this patient?
This patient has typical clinical features of chronic tinea pedis (TP). TP is characterized by slowly progressive pruritus of the feet, erythema and scaling between the toes, and extension to the soles and sides of the feet with a sharp border between the involved and uninvolved skin. TP is the most common dermatophyte infection and may be accompanied by infection of the hands (tinea manuum) or groin (tinea cruris). It may also extend into the toenails as well (onychomycosis). Acute TP, presenting with rapid onset vesicular or bullous lesions and severe pruritus, is usually self-limiting. However, chronic TP is usually persistent or relapsing. The organisms causing TP are widespread, and it is most commonly seen following exposure to public places while barefoot (eg, athletic facilities, public swimming pools).
Mild TP usually responds to topical antifungals (eg, terbinafine, miconazole, clotrimazole) in 1–4 weeks. More extensive disease or failure of topical agents may require oral therapy (eg, terbinafine, itraconazole, fluconazole). Patients with onychomycosis also require oral antifungals with a prolonged 12-week treatment course.
(Choice A) Griseofulvin is less effective than terbinafine and requires a longer treatment period.
(Choice C) Topical hydrocortisone is indicated for mild inflammatory dermatoses (eg, mild contact dermatitis or atopic eczema). It may be useful as adjunctive therapy for TP in patients with unbearable itching, but it should not be used alone as it may lead to prolonged infection.
(Choice D) Topical nystatin is indicated for treatment of skin infections due to Candida (eg, intertrigo) but is ineffective for TP.
(Choice E) Topical permethrin is indicated for scabies treatment. Scabies is characterized by scaly, erythematous linear papules involving the hands, wrists, and/or groin.
Educational objective:
Tinea pedis is a common superficial fungal infection of the foot with pruritic, erythematous, and well-demarcated lesions. Mild cases can be treated with topical antifungal agents. More severe cases or associated onychomycosis require oral antifungals.