White piedra: An uncommon cause of pseudonits in Northeast Mexico

ABSTRACT

Introduction: White piedra is a rare superficial mycosis caused by the genus Trichosporon. Its prevalence is higher among tropical climates and predominantly affects children and women. Less than 17 cases have been described in Mexico, none of them in the Northeast region. We present the first case reported in this zone. Case presentation A 27-year-old otherwise healthy woman presented to our clinic with a 1-month history of asymptomatic pseudonits on her scalp hair. Physical evaluation revealed numerous small white concretions over the majority of the hair shafts. At trichoscopic inspection, multiple white-yellowish ovoid nodules were observed. Direct microscopic examination with 20% potassium hydroxide (KOH) and blue cotton showed nodules composed of arthroconidia and hyphae over the hair shaft. Additionally, fungal culture was positive for Trichosporon inkin, confirming the diagnosis of white piedra. Treatment was initiated with ketoconazole shampoo and systemic itraconazole with favorable response. Discussion(s) Since the first case description by Beigel in Germany, most white piedra cases have been reported in tropical and humid climates. This mycosis typically affects females and subjects under 15 years of age. Some risk factors include poor hygiene, excess humidity, diabetes, and long, curly hair. In our case, the patient had curly hair and she constantly tied her hair up wet as she worked as a full-time nurse in a COVID-19 reference center. In our country, 50% of previous reported cases are from nontropical regions. Although infrequent in cosmopolitan areas in Northeast Mexico, white piedra should be considered in the differential diagnosis of pseudonits. Copyright © 2022