Diagnosis: Tinea capitis
On dermatoscopic examination (10× magnification), there were numerous “black dots” or broken hair shafts within patches of hair loss (FIGURE 3), which is indicative of tinea capitis.1,2 This condition causes hair shafts to break, creating “comma hairs” and black dots. The hairs are uniform in thickness and color and bend distally, like a comma.3
Tinea capitis (commonly called ringworm of the scalp) is a fungal infection caused by Trichophyton and Microsporum dermatophytes. It is the most common pediatric dermatophyte infection in the world; the usual age of onset is 5 to 10 years.2 The incidence of tinea capitis in the United States is not known because cases are no longer registered by public health agencies. That said, a Northern California study that tracked occurrences in children younger than 15 years from 1998 to 2007 found that the incidence was on the decline and lower in girls compared to boys (111.9 vs 146.4, respectively, in 1998; 27.9 vs 39.9, respectively, in 2007).4 Incidence rates were calculated per 10,000 eligible children.4
Tinea capitis can spread by contact with infected individuals and contaminated objects, including combs, towels, toys, and bedding.1 Fungal spores can remain viable on these surfaces for months.
In a study of 69 patients with tinea capitis (23 females, 46 males; mean age, 12 years), the risk factors for spreading infection included participation in sports, contact with an animal, a recent haircut, and use of a swimming pool.5
4 conditions you’ll want to rule out
The following conditions should be considered as part of the differential when a patient presents with an itchy scalp and/or hair loss.
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