Psoriasis of the scalp is characterized by scaling of the scalp along with crusted plaques. It is often accompanied by similar psoriatic plaques on the elbows, knees, and other areas of the body. Examination of our patient showed no psoriatic plaques.
Seborrhea of the scalp (also known as dandruff) is a very common diagnosis. However, it is unlikely to cause hair loss. It has widespread involvement of the scalp compared to tinea capitis, which is local and patchy. Our patient’s patches of hair loss indicated that seborrhea was unlikely.
Alopecia areata. Individuals develop this condition due to an autoimmune process affecting hair follicles. However, the resulting hair loss does not cause significant scaling, inflammation, scarring, or pain in the affected area. Further, this condition can cause the loss of the entire hair shaft.
Trichotillomania is an impulse control disorder that causes patients to pull out their own hair. There is no scaling of the scalp in this condition.
A dermatoscope can beuseful in making the Dx
Although clinical appearance and patient presentation are adequate to establish the diagnosis of tinea capitis, this case demonstrates the utility of a dermatoscope in making the diagnosis of tinea capitis. Previous studies have shown that dermoscopy allows for rapid identification of the broken hair shafts, which are a key distinction from alopecia areata.3,6
Microscopic inspection. Samples from the scaling of the scalp can be examined with potassium hydroxide (KOH) on a microscope slide. Hyphae, spores, and endo/ectothrix invasion can be seen through the microsope.
Continue to: Laboratory testing is helpful, but not needed.