Familial White Piedra Caused by Trichosporon inkin

White piedra is a superficial, chronic, asymptomatic mycoses caused by yeast fungi of the genus Trichosporon. It affects the hair, especially of the head, less frequently of the pubis, perineum, armpit, beard, mustache, eyebrows and eyelashes, and is characterized by the formation of soft nodules or fungal clusters. It affects all age groups and both sexes, predominantly women. Diagnosis is made by direct examination of the affected hair and culture on Sabouraud dextrose agar. The identification of species occurs through more specific identification procedures, such as mass spectrometry (MALDI-TOF) and PCR). The objective of this work is to report two cases of familial white piedra caused by T. inkin identified by PCR.

trose agar. Identification of causal fungi is determined by biochemical tests, currently, another more specific identification procedures such as mass spectrometry (MALDI-TOF) and molecular biology (PCR). Therapy mainly consists topical (shampoo) and systemic azolic derivates [1] [2].
We do not know its magnitude (incidence, prevalence), geographic distribution and in members of the same family, only by case reports or systematic reviews, it is not mandatory notification in the health sector, it is frequently confused and managed as head lice [3] [4] [5]. We present 2 cases in a family diagnosed by molecular biology

Case Report
Case 1 A 7-year-old female, a resident of Acapulco, Guerrero, she has an 8-month history with whitish structures in her hair, was treated treatment for head lice without improvement.
Examination revealed a normal-looking scalp, abundant, long hair with white nodules were identified throughout the hair, with a predominance in the occipital region (Figure 1(A)), which were better observed with wet hair. To the touch, the concretions are rough, soft consistency.

Case 2
A 52-year-old female, grandmother of the first case, with diabetes mellitus 2, upon examination, numerous concretions of a soft consistency adhered to the hair ( Figure 1(B)), onset 5 months ago accompanied by itching in the occipital region, without previous treatment.
The time interval between cases was 6 months, history of long hair, habit of tying it up wet and living in the same house.
Clinically, it corresponds to white piedra, and samples of parasitized hair were  The treatment was to wash the hair daily with 2% ketoconazole shampoo, observing improvement after one month, followed by three months, with no relapses.

Discussion
White piedra was first described as a fungal disease by Beigel in 1865, who isolated the fungus from a wig, but Rabenhorst gave it the name Pleurotus beigelii [7]. In 1890 Behrend described another case affecting the beard and the isolated microorganism received the name of Trichosporon ovoides. In 1902 Vuillemin named all species so far described as T. beigelii [8]. In 1994, Gueho et al. rearranged the genus Trichosporon in six species: T. asahii, T. cutaneum, T. asteroides, T. mucoides, T. inkin and T. ovoides. [9]. Currently, based on several phenotypic, biochemical, and molecular studies, there are about 51 Trichosporon species, from which 16 have clinical relevance [8].
A systematic literature review was conducted using PubMed, Embase, Academic, SciELO, Google and Virtual Library to 6 June 2022 using the words "white piedra", "white piedra scalp", "white piedra mycoses", "piedra blanca cuero cabelludo", "couro cabeludo de pedra branca".  The patients were treated with topical azoles and/or systemic triazoles. There is no consensus on the treatment of this mycosis, El Attar et al. [15] compared three therapy modalities: 1) topical azoles, 2) topical and oral azole; and 3) topical azole and oral terbinafine. The percentages of cure were in 1) 50% in 12 weeks; 2) 75% in four weeks; 3) 60% in eight weeks, the combination of topical and oral azolic drugs showed to be the best therapy.
In 2012 in Brazil Richini et al. [5] published the case of a family with white piedra in members of the same family (mother and 2 children) diagnosed by molecular biology, our case in grandmother and granddaughter is the second and the first in Mexico. The differential diagnosis of white piedra includes black piedra, trichobacteriosis, pediculosis capitis and hair casts [2].

Conclusions
Case reports of familial white piedra are few, this is the second by Trichosporon inkin diagnosed by molecular biology in Latin America and the first in Mexico.
It is important to sensitize the clinical doctors that when faced with a suspected case of head lice, one of the differential diagnoses is white stone and that molecular biology is the gold standard for identifying the etiological agents.

Ethics Declaration
Written informed consent was obtained from the mother of the minor and the grandmother for the publication of the cases and clinical images.