Tinea Cruris (Jock Itch)

ESSENTIALS OF DIAGNOSIS
Marked itching in intertriginous areas, usually sparing the scrotum.
Peripherally spreading, sharply demarcated, centrally clearing erythematous lesions.
May have associated tinea infection of feet or toenails.
Laboratory examination with microscope or culture confirms diagnosis.
General Considerations
Tinea cruris lesions are confined to the groin and gluteal cleft. Intractable pruritus ani may occasionally be caused by a tinea infection.
Clinical Findings
A. SYMPTOMS AND SIGNS
Itching may be severe, or the rash may be asymptomatic. The lesions have sharp margins, cleared centers, and active, spreading scaly peripheries. Follicular pustules are sometimes encountered. The area may be hyperpigmented on resolution.
B. LABORATORY FINDINGS
Hyphae can be demonstrated microscopically in KOH preparations. The organism may be cultured readily.
Differential Diagnosis
Tinea cruris must be distinguished from other lesions involving the intertriginous areas, such as candidiasis, seborrheic dermatitis, intertrigo, psoriasis of body folds (“inverse psoriasis”), erythrasma, and rarely tinea versicolor. Candidiasis is generally bright red and marked by satellite papules and pustules outside of the main border of the lesion. Candida typically involves the scrotum. Tinea versicolor can be diagnosed by the KOH preparation. Seborrheic dermatitis also often involves the face, sternum, and axillae. Intertrigo tends to be more red, less scaly, and present in obese individuals in moist body folds with less extension onto the thigh. Inverse psoriasis is characterized by distinct plaques. Other areas of typical psoriatic involvement should be checked, and the KOH examination will be negative. Erythrasma is best diagnosed with Wood's light—a brilliant coral-red fluorescence is seen.
Treatment
A. GENERAL MEASURES
Drying powder (eg, miconazole nitrate [Zeasorb-AF]) should be dusted into the involved area in patients with excessive perspiration or occlusion of skin due to obesity. Underwear should be loose-fitting.
B. LOCAL MEASURES
Any of the preparations listed in the section on tinea corporis may be used. There is great variation in expense, with miconazole, clotrimazole, butenafine, and terbinafine available over the counter and usually at a lower price. Terbinafine cream is curative in over 80% of cases after once-daily use for 7 days.
C. SYSTEMIC MEASURES
Griseofulvin ultramicrosize is reserved for severe cases. Give 250–500 mg orally twice daily for 1–2 weeks. One week of either itraconazole, 200 mg daily, or terbinafine, 250 mg daily, is also effective.
Prognosis
Tinea cruris usually responds promptly to topical or systemic treatment. It may leave behind postinflammatory hyperpigmentation.

No comments:

Post a Comment