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Key Features

  • Dermatophytes become attached to the superficial layer of the epidermis, nails, and hair, where they proliferate

  • Fungal infection should be suspected with any red and scaly lesion

  • Classified into tinea capitis, tinea corporis, tinea cruris, tinea pedis, tinea unguium

Clinical Findings

  • Tinea capitis

    • Thickened, broken-off hairs with erythema and scaling of underlying scalp are the distinguishing features

    • Hairs are broken off at the surface of the scalp, leaving a "black dot" appearance

    • Diffuse scaling of the scalp and pustules are also seen

    • A boggy, fluctuant mass on the scalp called a kerion, represents an exaggerated response to the organism

  • Tinea corporis

    • Presents either as annular marginated plaques with a thin scale and clear center or as an annular confluent dermatitis

  • Tinea cruris

    • Symmetric, sharply marginated lesions in inguinal areas

  • Tinea pedis

    • Presentation is with red scaly soles, blisters on the instep of the foot, or fissuring between the toes

  • Tinea unguium (onychomycosis)

    • Loosening of the nail plate from the nail bed (onycholysis), giving a yellow discoloration, is the first sign of fungal invasion

    • Thickening of the distal nail plate then occurs, followed by scaling and a crumbly appearance of the entire nail plate surface

    • Usually only one or two nails are involved


  • Tinea capitis

    • Causative organisms: Microsporum canis and Trichophyton tonsurans

    • Fungal culture should be performed in all suspected cases

  • Tinea corporis

    • Causative organisms Trichophyton mentagrophytes, Trichophyton rubrum, and M canis

    • Diagnosis is made by scraping thin scales from the border of the lesion, dissolving them in 20% potassium hydroxide (KOH), and examining for hyphae

  • Tinea cruris: causative organisms are T rubrum, T mentagrophytes, and Epidermophyton floccosum

  • Tinea pedis

    • Causative organisms: T rubrum and T mentagrophytes

    • Diagnosis is more common in the prepubertal child, although still most commonly seen in postpubertal males

  • Tinea unguium

    • Causative organism: T rubrum

    • Diagnosis is confirmed by KOH examination and fungal culture


  • If hair is involved, systemic therapy is necessary

    • Griseofulvin (20 mg/kg/d; maximum 500 mg/dose) and terbinafine (62.5 mg/d, < 20 kg–125 mg/d, 20–40 kg–250 mg/d, > 40 kg) are both effective

    • Terbinafine does not work for M canis

  • For nails, daily administration of topical ciclopirox 8% (Penlac nail lacquer) can be considered, as can terbinafine for 6–12 weeks or pulsed-dose itraconazole (50 mg/twice a day < 20 kg–100 mg/twice a day, 20–40 kg–200 mg/twice a day, > 40 kg) given in three 1-week pulses separated by 3 weeks

  • Tinea corporis, tinea pedis, and tinea cruris

    • Can be treated effectively with topical medication after careful inspection to make certain that the hair and nails are not involved

    • Recommended agents: any of the imidazoles, allylamines, benzylamines, or ciclopirox applied twice daily for 3–4 weeks

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