The patient is a 54 year old female who presents with alopecia. Clinical exam reveals black dots on her scalp with scale, pustules and erythema. She also has areas of scarring alopecia.
Diagnosis: Black dot tinea.
Discussion: Black dot tinea capitis is a form of dermatophytosis primarily affecting the hair shaft and hair follicle. It is also sometimes called ringworm of the scalp or tinea tonsurans, because Tinea tonsurans accounts for the vast majority of the cases. The vast majority of cases occur in children. Adult cases such as this case are unusual. Scarring alopecia with permanent hair loss may occur.
The black dots are the stubs of hair shafts that result when hair shafts become brittle and break off after being infected by the fungi. The fungal spores are present within the hair shafts (endothrix position) on histologic examination.
References: Trovato MJ, Schwartz RA, Janniger CK. Tinea capitis: current concepts in clinical practice. Cutis. Feb 2006;77(2):93-9.