A 30-year-old man comes to the office due to a rash. For the last 3 weeks, he has had a slowly enlarging, pruritic rash at the left groin. The patient had a similar rash 2 months ago that resolved after topical treatment with miconazole; he has since been careful to dry his skin thoroughly after bathing. Medical history is unremarkable. The patient has 1 long-term sexual partner and does not use tobacco, alcohol, or illicit drugs. Vital signs are normal. BMI is 24 kg/m². Examination shows an annular plaque with a scaly border in the left groin; scrotal skin is normal. Potassium hydroxide microscopy of skin scrapings from the lesion reveals segmented hyphae. Which of the following is the most appropriate next step in management of this patient?

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Quizplus · Accepted Answer

11ec25c8_d390_509d_bc81_0b7565b999da_MD0003_00 This patient has a scaly, pruritic rash at the groin with sparing of the scrotum. Potassium hydroxide microscopy showing fungal elements confirms the diagnosis of tinea cruris (TC). TC, often called jock itch, is a common dermatophyte infection caused by Trichophyton rubrum and similar species. Recurrent TC is common and suggests reexposure to an external source or autoinfection from a concurrent dermatophyte infection elsewhere on the body (eg, tinea pedis, tinea corporis, onychomycosis). Therefore, the patient should have a thorough skin inspection and have any other sites of infection treated; untreated foci of dermatophyte infection can lead to continuing reinfection and potential secondary bacterial infection (eg, gram-positive cellulitis). Other measures for preventing recurrence include thorough drying of skin after bathing, use of absorbent natural-fiber (eg, cotton) underwear, and avoidance of tight-fitting or occlusive clothing. Topical antifungals (eg, miconazole, tolnaftate) are usually effective for eradication, and localized disease recurrence can be treated again with topical agents. (Choice B) Fungal blood cultures are most commonly used for evaluation of sepsis or fever of unknown origin in patients with immune suppression, indwelling vascular access devices, or large-area burns. Tinea infections are generally superficial, and fungemia and other invasive complications are rare. (Choice C) Severe or widespread dermatophyte infection can be seen in patients with impaired immunity, especially those with HIV infection or on systemic glucocorticoid therapy. Patients with immunoglobulin deficiencies (eg, selective IgA deficiency, common variable immunodeficiency) typically develop recurrent sinopulmonary and gastrointestinal bacterial infections rather than dermatophyte infection. Recurrence of uncomplicated TC is common in healthy patients and does not suggest an underlying immune disorder. (Choice D) Topical corticosteroids (eg, hydrocortisone) are not recommended in TC or other superficial dermatophyte infections because they are associated with worsening of the infection. (Choice E) Selenium sulfide is indicated for the treatment of tinea (pityriasis) versicolor (eg, hypo/hyperpigmented macules on trunk and upper extremities) and seborrheic dermatitis of the scalp; these conditions are not dermatophyte infections. Selenium sulfide is not recommended for TC. Educational objective: Recurrent tinea cruris is common and suggests reexposure to an external source or autoinfection from a concurrent dermatophyte infection elsewhere on the body (eg, tinea pedis, tinea corporis, onychomycosis). Patients should have a thorough skin inspection, and any other sites of infection should be treated.

A 30-Year-Old Man Comes to the Office Due to a Rash