Why Does this Boy Have an Itchy, Scaly Scalp With Hair Loss?

A 5-year-old boy presented with itching, scaling, and an area of hair loss with a duration of 6 months in the right parietal area on the scalp. There was no history of plucking, pulling, or twisting of hair. Review of systems was negative. The family had acquired a dog a year ago, and the dog had appeared healthy and had normal fur. There was no family history of similar hair loss or skin lesions.

Examination of the right parietal scalp revealed fine scaling, patchy hair loss with broken hair shafts, and a black dot appearance. The hair in the affected area was of irregular length. The results of the hair-pull test were negative, and there was no cervical, occipital, or postauricular lymphadenopathy. The rest of the examination results were unremarkable.

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