White piedra in children

BACKGROUND

White piedra is a fungal infection of the hair shaft caused by species of Trichosporon. Rarely has this infection been reported in the United States. Historically, infected individuals required shaving of their hair to achieve clearance of the infection.

OBJECTIVE

We sought to describe 8 cases of Trichosporon scalp infections seen in the northeastern United States.

METHODS

We conducted chart review and prospective evaluation of 7 girls and 1 boy seen in two dermatology practices in New Haven, Conn, and New York, NY.

RESULTS

Seven girls, ages 4 to 16 years old, and one 4-year-old boy were determined to have Trichosporon scalp infection, all through culture. Of the 8 children who were available for follow-up, 7 had clearance of their infection with a combination of oral azole antifungal medication and azole antifungal shampoo, without shaving the scalp hair.

LIMITATIONS

This was a sample of patients from a localized region of the United States.

CONCLUSIONS

White piedra is emerging as a commonly seen hair and scalp infection in the northeastern United States. Contrary to prior publications, scalp and hair infection may be successfully treated with a combination of oral azole antifungals and shampoos without shaving the scalp.

Superficial fungal infections

Superficial fungal infections arise from a pathogen that is restricted to the stratum corneum, with little or no tissue reaction. In this Seminar, three types of infection will be covered: tinea versicolor, piedra, and tinea nigra. Tinea versicolor is common worldwide and is caused by Malassezia spp, which are human saprophytes that sometimes switch from yeast to pathogenic mycelial form. Malassezia furfur, Malassezia globosa, and Malassezia sympodialis are most closely linked to tinea versicolor. White and black piedra are both common in tropical regions of the world; white piedra is also endemic in temperate climates. Black piedra is caused by Piedraia hortae; white piedra is due to pathogenic species of the Trichosporon genus. Tinea nigra is also common in tropical areas and has been confused with melanoma.

Tinea corporis, tinea cruris, tinea nigra, and piedra

Tinea infections are among the most common dermatologic conditions throughout the world. To avoid a misdiagnosis, identification of dermatophyte infections requires both a fungal culture on Sabouraud's agar media, and a light microscopic mycologic examination from skin scrapings. Topical antifungals may be sufficient for treatment of tinea corporis and cruris and tinea nigra, and the shaving of hair infected by piedra may also be beneficial. Systemic therapy, however, may be required when the infected areas are large, macerated with a secondary infection, or in immunocompromised individuals. Preventative measures of tinea infections include practicing good personal hygiene; keeping the skin dry and cool at all times; and avoiding sharing towels, clothing, or hair accessories with infected individuals.

Trichosporon beigelii infection presenting as white piedra and onychomycosis in the same patient

Trichosporon beigelii is a fungal organism that causes white piedra and has occasionally been implicated as a nail pathogen. We describe a patient with both hair and nail changes associated with T. beigelii.

Clinical and mycological study of scalp white piedra in the State of Paraíba, Brazil

White piedra is a superficial mycoses characterized by nodules on the hair shaft, caused by the basidiomycetous yeasts. In the present study, clinical and mycological findings of scalp white piedra caused by Trichosporon spp. are related. Twenty three cases of scalp white piedra were observed with a high incidence in women (87%) and preschool children from 2 to 6 (74%) years old. These groups presented a relationship of dependence with this infection. Despite the low socio-economic status, poor standards of hygiene, (48% of the patients) as well as the fact that 30.4% of the children shared the same nursery, these factors were not significant for the transmission of the mycosis. These were the first reports of scalp white piedra in João Pessoa city, Paraíba, Brazil.

X-ray microanalysis of black piedra

The elements present in the fungal structures produced by Piedraia hortae in vivo and in vitro have been investigated using electron microscopy X-ray microanalysis. Phosphorus, sulphur and calcium were detected in the nodules which developed on hair and on colonies on culture. These elements belong to the extracellular material that compacts the pseudoparenchymatous organization of the fungus. They may be present due to the capacity of melanin-like pigments to sequester ions and/or they may form part of the sulphates and phosphates of the polyanionic mucopolysaccharides that constitute the extracellular material. Environmental contaminants such as aluminium, silicon and iron were detected exclusively on the surface of the nodule. They were deposited or linked to the residual molecules produced during the breakdown of the cuticular keratin. The advantages of these techniques for elucidating the chemical nature of fungal structures are discussed.

Ultrastructural aspects of hair digestion in black piedra infection

The ultrastructural pattern of human hair infection by Piedraia hortae in vivo has been studied. The fungus destroyed the cuticular layers of the hair and was able to penetrate deeply into the cortex. The course of destruction of human hair is described and compared with that produced by other fungi. Two well-defined types of cortex digestion were characterized. The slow rate of keratin degradation at the cortex together with the compacted stromatic organization of the nodules are argued as the main reasons that guarantee the long survival of the fungus, and therefore the chronic course of the disease. The data provided in this paper may help to understand the mechanisms that regulate the pathogenicity of this fungus.

[White piedra. Report of a case]

The most common superficial mycosis caused by Trichosporon beigelii is white piedra. We report a 18 years old male that had in several hairs of the scalp, white-yellowish nodules of 1 mm diameter, agglutinated or forming chains, even forming threads, with a greasy aspect. Trichosporon beigelii was identified in cultures. Oral and topical antimycotics were prescribed and the patient was lost from follow up.

Taxonomic position of deep-seated, mucosa-associated, and superficial isolates of Trichosporon cutaneum from trichosporonosis patients

Clinical isolates of Trichosporon cutaneum, the causative agent of trichosporonosis, were identified on the basis of DNA relatedness. Of the 10 strains from deep-seated and mucosa-associated infections, 9 were identified as T. asahii and 1 was identified as T. ovoides. The two superficial strains were identified as T. cutaneum and a variety of T. montevideense. These findings suggest that T. cutaneum is a heterogeneous species in clinical samples and that the causative agents of trichosporonosis exist in four or more species.

White piedra and Trichosporon species in equatorial Africa. III. Identification of Trichosporon species by slide agglutination test

Fifty-two Trichosporon strains isolated from Gabonese female patients 15-60 years, were studied. The identity of these strains was established by two different methods: the method proposed by Guého et al. (1992), based on mycological criteria, and a slide agglutination method performed with monospecific antisera prepared in our laboratory. The final results show a perfect correlation between the two methods, which allowed us to identify 25 strains of T. mucoides, 21 strains of T. inkin and seven strains of T. asahii. The results of the agglutination tests performed with 24-h-old subcultures grown on Sabouraud glucose agar are available in less than 15 mins. In the light of these results, it appears that this method, which is rapid and easy to perform and reproduce, may readily be used in hospital laboratories. In addition, this method allowed us to verify the presence of antigens common to the genera Cryptococcus and Trichosporon, which were easily shown by the use of crude sera. The fact that the anti-Trichosporon monospecific sera lose their capacity to agglutinate Cryptococcus neoformans proves their high specificity.

White piedra and Trichosporon species in equatorial Africa. I. History and clinical aspects: an analysis of 449 superficial inguinal specimens

White piedra is a hair infection characterized by nodules composed of fungal elements which envelop the hair shaft. Classically, this infection was considered to be produced by an asexual yeast-like fungus, Trichosporon beigelii. At present, in accordance with studies carried out previously, this species is subdivided into six newly defined distinct species (T. asahii, T. ovoides, T. inkin, T. mucoides, T. asteroides and T. cutaneum), all belonging to the class Basidiomycetes. Although widespread, white piedra has not previously been described in tropical regions of Africa. The present study, carried out in Libreville (Gabon), an equatorial region of Africa, shows that the incidence of this infection is quite high (18% of 449 inguinal specimens) in the female population aged 15-60 years, with a predominance in young patients (15-44 years). The relationship between the clinical manifestations and the specific hair lesions is also detailed. Three species belonging to the genus Trichosporon were identified: T. mucoides, T. asahii and T. inkin.

White piedra and Trichosporon species in equatorial Africa. II. Clinical and mycological associations: an analysis of 449 superficial inguinal specimens

Eighty-one of 449 Gabonese female patients examined were found to be positive for genitopubic white piedra. The association with trichobacteriosis is frequent (53 cases), and mostly seen with inguinal intertrigo. Fifty-two strains belonging to the genus Trichosporon were isolated from genital hairs as well as from inguinal intertrigo lesions. These strains were identified in accordance with previously defined morphological and biochemical criteria. Three species were recognized: T. mucoides (25 strains), T. inkin (20 strains) and T. asahii (seven strains). Their macroscopic and microscopic morphological properties, as well as their ability to reduce tetrazolium, were determined. In addition, the study of the clinical and pathogenic associations in which each of these strains was involved revealed some of their particular properties.

A new Brevibacterium sp. isolated from infected genital hair of patients with white piedra

A new aerobic gram-positive non-sporeforming bacillus has been isolated from infected genital hair of patients with white piedra in association with Trichosporon beigelii. This species has been characterised morphologically, nutritionally, by DNA base composition, cell-wall analysis and cellular fatty-acid profile on the basis of 14 isolates. The G+C content of DNA is 63.05 mol%. Cell walls possess meso-diaminopimelic acid (Type IV) and the sugars glucose, galactose, xylose and ribose; mycolic acids are not present. The species has a distinct colonial and microscopic morphology, is strongly proteolytic and produces methanethiol. These findings and the cellular fatty-acid profile are compatible with the genus Brevibacterium. A new species is proposed based on the following characters: colonial and microscopic growth and morphology; conditions for rod-to-coccus cycle; ribose utilisation; and tellurite reduction. The type strain has been named Brevibacterium mcbrellneri E2cr (ATCC 49030). The strong proteolytic properties may be the mechanism of pathogenesis.

Ultrastructure of black piedra

Black piedra or nodular trichomycosis is a superficial mycosis of the hair shaft, prevalent in the tropical areas of South America and Asia and caused by the fungus Piedraia hortai. By scanning electron microscopy the invasion of the hair keratin and the elimination of spores through canals was seen. Transmission electron microscopy showed a complex, well-organized microsystem, in which cement-producing hyphae constitute the pseudoparenchyma. Both sexual and asexual reproduction were found. Sexual reproduction gives rise to ascospores and asexual reproduction to arthrospores. The ascospores were found in thick-walled bags, the asci; the arthrospores, that undergo gemmation, are eliminated through canals, disseminating the disease.

Cepholosporium acremonium. A new strain of fungus causing white piedra

A strain of fungus (CZ408) was isolated from white piedra of a female child. Mycological identification showed that it is the first case in the world. Asymptomatic white nodules were noted on the hair of the scalp, and they were distributed irregularly along the shaft 4-10 cm from the scalp. The nodules, hard, not easily broken or removed, consist of hyphae, spores and metabolic materials around the hair. Oral antimycotic drugs are effective in treating this disease.

White piedra: evidence for a synergistic infection

To determine the relative roles of coryneform bacteria and Trichosporon beigelii in the pathogenesis of genital white piedra, scrotal hair from 10 subjects was studied. Hairs were examined by light microscopy to determine the relative proportions of each organism, and were also cultured for coryneforms and yeast. Histologically, hair nodules from five out of nine cases showed a mixture of yeasts and bacteria, four had bacteria alone, and none showed yeast alone. Five strains of T. beigelii were cultured, two strains of Saccharomyces cerevisiae and 22 strains of coryneforms. The isolates were tested for synergism by a plate-overlay method. Growth of coryneforms occurred over and around sections of the plate inoculated with T. beigelii but not around the control yeast, S. cerevisiae. There were strain differences in the stimulatory response of both T. beigelii and coryneform strains. In reverse experiments coryneforms did not enhance growth of T. beigelii. It was concluded that white piedra is a mixed infection caused by the synergistic action between T. beigelii and a specific coryneform bacteria resulting in invasion of the hair cuticle and cortex.

Antifungal susceptibility testing of Trichosporon beigelii to imidazole compounds

Twenty-two strains of Trichosporon beigelii have been tested for susceptibility to imidazole compounds. Ten strains were isolated from untreated genital white piedra lesions and 12 were from the same patients following treatment failure with imidazole compounds. Agar dilution and disk elution methods were compared using two media: yeast nitrogen base and antibiotic assay medium 3 (Difco). Antifungal agents tested were econazole, miconazole, ketoconazole, clotrimazole, and amphotericin B in concentrations of 0.0625-32 micrograms/mL. The most consistent results occurred with antibiotic assay medium 3 and the agar dilution method giving minimal inhibitory concentrations between 0.0625 and 0.25 micrograms/mL. Using yeast nitrogen base agar, minimal inhibitory concentrations were higher ranging from 0.0625 to 2.0 micrograms/mL. End points of growth in the disk elution method were not clearly delineated and ranged from 0.0625 to 8.0 micrograms/mL. The distribution of minimal inhibitory concentrations obtained using different media and methods were compared by chi 2 analysis, and the medium was found to significantly change the minimal inhibitory concentrations. There was no difference in the susceptibility of strains of T. beigelii to imidazole compounds whether isolated before or after treatment. It was concluded that in vitro susceptibility of T. beigelii to imidazole compounds did not necessarily predict efficacy in vivo.

Genital white piedra: epidemiology, microbiology, and therapy

The epidemiology of genital white piedra was investigated in 166 young men with a variety of genital complaints. Trichosporon beigelii was isolated from sixty-six (40%) of the cultured scrotal hairs. Infection was more common among black patients--54% of those examined, compared to 16% of white patients and 30% of "others" (p less than 0.001). There was no relationship between infection and foreign travel. White piedra was also found in young women, but less frequently than in young men (14% vs 40%, respectively). Transmission rarely occurred from person to person. Occasionally multiple body sites were simultaneously infected. A relationship may exist between T. beigelii and Corynebacterium concurrently infecting genital hair shafts. Eradication of infection was extremely difficult, despite in vitro sensitivity to antifungal agents. Spontaneous remissions occurred, however, in some patients.

Morphology of Piedra hortal

Piedra hortai, an ascomycete causing black piedra, was studied with light and electron microscopy. The nodule on the hair contains septate hyphae, asci and free ascospores, all of which were smaller than those previously reported. A mode of spread of infection is suggested.

[Balck piedra in chimpanzees from Zaire]

Black piedra was present in 21 of 72 museum pelts of chimpanzees (Pan paniscus and Pan satyrus) from Zaïre. In the absence of culture, the mycological characteristics observed in vivo, although insufficient to allow a definite identification of the Piedraia species involved, are almost identical with those of Piedraia quintanilhae Van Uden, De Barros-Machado & Castelo-Branco, 1963.