Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 6-14: Fungal Infections of the Skin + Key Features Download Section PDF Listen +++ +++ 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 Download Section PDF Listen +++ +++ Symptoms and Signs ++ Itching may be severe, or the rash may be asymptomatic Typical lesions are erythematous and sharply demarcated, with central clearing and active, spreading scaly peripheries Follicular pustules are sometimes encountered The area may be hyperpigmented on resolution +++ Differential Diagnosis ++ Other lesions of the intertriginous area Erythrasma: best diagnosed with Wood light—a brilliant coral-red fluorescence is seen Candidiasis Generally bright red and marked by satellite papules and pustules outside of the main border of the lesion Candida typically involves the scrotum Seborrheic dermatitis: also often involves the face, sternum, axillae, and genitalia (but not the crural folds) Intertrigo Tends to be less red, less scaly Tends to be present in obese individuals in moist body folds with less extension onto the thigh Psoriasis of body folds ("inverse psoriasis") Inverse psoriasis is characterized by distinct plaques Other areas of typical psoriatic involvement should be checked The KOH examination will be negative + Diagnosis Download Section PDF Listen +++ +++ Laboratory Tests ++ Hyphae can be demonstrated microscopically in KOH preparations The organism may be cultured + Treatment Download Section PDF Listen +++ +++ Local measures ++ See preparations listed in Table 6–2 Terbinafine cream is curative in over 80% of cases after once-daily use for 7 days +++ Systemic measures ++ Itraconazole, 200 mg once daily orally, or terbinafine, 250 mg once daily orally, for 1 week, can be effective Griseofulvin ultramicrosize is reserved for severe cases; give 250–500 mg twice daily orally for 1–2 weeks + Outcome Download Section PDF Listen +++ +++ Prevention ++ Drying powder (eg, miconazole nitrate [Zeasorb-AF]) can be dusted into the involved area in patients with excessive perspiration or occlusion of skin due to obesity +++ Prognosis ++ Usually responds promptly to treatment but often recurs +++ When to Refer ++ If there is a question about the diagnosis, if recommended therapy is ineffective, or if specialized treatment is necessary + References Download Section PDF Listen +++ + +Kramer ON et al. Clinical presentation of terbinafine-induced severe liver injury and the value of laboratory monitoring: a critically appraised topic. Br J Dermatol. 2017 Nov;177(5):1279–84. [PubMed: 28762471] + +Rajagopalan M et al. Expert Consensus on The Management of Dermatophytosis in India (ECTODERM India). BMC Dermatol. 2018 Jul 24;18(1):6. [PubMed: 30041646]