Making the Diagnosis of Tinea Capitis with Trichoscopy.
Comma Hairs & Corkscrew Hairs Among the More Specific Trichoscopic Findings of Tinea Capitis
Tinea capitis is a common scalp fungal infection and among the more common reasons that children age 5-10 lose hair. Other reasons for hair loss in this age group include alopecia areata, telogen effluvium, trichotillomania, loose anagen syndrome and hair shaft disorders.
The gold standard way to diagnose tinea capitis is by taking a sample and sending it off to the lab to grow it up (i.e. for “culture). Trichoscopy however is proving extremely useful for diagnosis as well. Even though the precise species can’t be identified with trichoscopy, the diagnosis can be made and the patient can be started on therapy while awaiting confirmation of the specific species.
In 2020, the team of Anna Waśkiel-Burnat, Adriana Rakowska, Mariusz Sikora, Piotr Ciechanowicz, Małgorzata Olszewska and Lidia Rudnicka from the Department of Dermatology in Warsaw, Poland set out to review all the articles published in medical journals related to the “trichoscopy” of tinea capitis. What they produced is truly a helpful publication summarizing just how common these various trichoscopic signs. They calculated the sensitivity, specificity, positive predictive value and negative predictive value for a variety of signs. The group showed that “comma hairs” were among the more common of the characteristic signs and were found in about 50 % of cases. Corkscrew hairs, morse code hairs, zigzag hairs, bent hairs, block hairs and i hairs were less commonly found but all carried extremely high specificity of 99-100 %. In other words, if any of these findings were seen on the scalp with trichoscopy, it was almost certain that the patient had a diagnosis of tinea capitis.
This study highlighted the usefulness of trichoscopy to diagnose tinea capitis. The article is free online for anyone interested.
This article was written by Dr. Jeff Donovan, a Canadian and US board certified dermatologist specializing exclusively in hair loss.