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around the base of the foot and often with extension in between the toes.
Coincident onychomycosis is common and presents with toe nail thickening
and subungual debris. Tinea manuum is the name for dermatophyte
infection of the palms and is characterized by an extremely dry and
sometimes fissured appearance that can mimic hand dermatitis. Often,
patients with tinea manuum will have tinea pedis as well and present with
both feet and one hand infected.


FIGURE 66.11 Tinea corporis (ringworm). Note the annular appearance, central
clearing, and “active” scaly border that demonstrate hyphae on potassium hydroxide
examination. (Reprinted with permission from Goodheart HP. Goodheart’s Photoguide
of Common Skin Disorders . 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins;
2003.)


FIGURE 66.12 Tinea capitis. Alopecia with the “black dot” sign of broken hairs.
(Reprinted with permission from Fleisher GR, Ludwig S, Baskin MN. Atlas of Pediatric
Emergency Medicine . Philadelphia, PA: Lippincott Williams & Wilkins; 2004.)

In North America, tinea capitis is most commonly caused by infection
with Trichophyton tonsurans or Microsporum canis. Infection can manifest
as scaling patches of alopecia, areas of distinct alopecia with broken hairs
that manifest as “black dots” ( Fig. 66.12 ), diffuse scaling with little
alopecia, or an acute boggy plaque (kerion) ( Fig. 66.13 ). Tinea capitis and
other dermatophyte infections of hair-bearing areas (eyebrow, beard, etc.)
usually require systemic therapy because these are deeper infections of the
hair shaft and follicle. Four to 8 weeks of griseofulvin (children over 2
years) or 2 to 6 weeks of terbinafine (children over 4 years) are commonly
used therapies. In children under 2 years, oral fluconazole can be used, but
topical therapy with an azole (e.g., clotrimazole) or an allylamine (e.g.,

terbinafine) may be effective if the hairs are fine.


FIGURE 66.13 Tinea capitis with kerion. Note the boggy swelling from inflammation.
(Reprinted with permission from Fleisher GR, Ludwig S, Baskin MN. Atlas of Pediatric
Emergency Medicine . Philadelphia, PA: Lippincott Williams & Wilkins; 2004.)

Dermatophytes can be cultured by sending skin scrapings on a sterile
tooth brush or in a sterile urine cup to the laboratory. Of note, some labs
standardly perform a more broad fungal culture instead of a dermatophytespecific culture. Incidental, nonpathologic soil molds can grow on broader
fungal cultures and the results must be interpreted with caution. Topical
therapy for dermatophyte infections with azole agents such as clotrimazole
or allylamines such as terbinafine is usually effective. In hair-bearing areas
(scalp, beard, eyebrow) and nail infections, oral antifungals are usually
needed to penetrate the hair follicle or nail. Tinea manuum and severe tinea
pedis may also require oral antifungals due to the thickness of the stratum
corneum.
Candida Infections