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griseofulvin (15 to 20 mg/kg/day in two divided doses) will usually resolve the
problem.
Tinea Capitis
Although tinea capitis is commonly caused by Microsporum species and
Trichophyton tonsurans , the two forms have different clinical appearances. The
Microsporum species generally causes round patches of scaling alopecia ( Fig.
88.21 ). Illumination of a lesion with a Wood lamp gives a blue-green
fluorescence. Kerion formation can occur as a swollen, boggy abscess. The
Trichophyton species usually causes scattered alopecia with seborrheic-like
scaling, not always oval or rounded; the alopecia is irregular in outline with
indistinct margins. Normal hairs grow within the patches of alopecia. At times,
the hairs break off at the surface of the scalp, leaving a “black dot” appearance (
Fig. 88.22 ). Diffuse scaling may simulate dandruff, and although minimal hair
loss is present, it is not perceived. Wood light examination of lesions caused by
Trichophyton species does not produce fluorescence. The organism can cause a
folliculitis, suppuration, and kerion formation ( Fig. 88.23 ). Diagnosis is made
by culturing the affected scalp area. The clinician should consider the presence of
tinea capitis when a nonresponsive seborrheic or atopic dermatitis of the scalp is
present, black dots are seen, occipital adenopathy is present, or increased scaling
follows the use of topical steroids. If a kerion is present, the swelling (allergic
reaction to the fungus) can be controlled by a combination of griseofulvin and
prednisone. It is important to treat with an oral agent and not simply with a
topical shampoo or cream; the latter is ineffective and can temporarily improve
the tinea capitis while rendering subsequent cultures falsely negative, greatly
complicating the case.