Black Dot Ringworm Research Articles

ステロイド剤外用中に生じた <i>Trichophyton rubrum </i>による Black Dot Ringworm の 1 例

ステロイド剤外用中に生じた <i>Trichophyton rubrum </i>による Black Dot Ringworm の 1 例

頚部にみられた<I>Trichophyton tonsurans</I> によるBlack Dot Ringwormの1例

頚部にみられた<I>Trichophyton tonsurans</I> によるBlack Dot Ringwormの1例

Extra-Scalp Black Dot Ringworm Caused by Trichophyton tonsurans Among Contact Sports Players

We describe here two patients with tinea corporis exhibiting black dot ringworm (BDR). A cluster of black dots was observed on the extensor surfaces of the extremities of two rather hairy male patients, a 15-year-old judo practitioner and a 26-year-old combined martial arts fighter, during treatment of tinea corporis with topical antimycotics. Direct KOH examination showed that the black dots were composed of degenerated hair with numerous arthroconidia and were indistinguishable from BDR of tinea capitis. Trichophyton tonsurans was isolated from the dots of both patients. Although they were diagnosed with tinea corporis, they required 2-3months of treatment with oral terbinafine. Dermatologists should be aware that BDR can appear on areas of the skin other than the scalp.

Clinical and mycological analysis of 241 cases of tinea capitis in Guangzhou region

Objective To make a clinical and mycological analysis of tinea capitis in Guangzhou region. Methods A retrospective analysis was performed on 241 cases of tinea capitis collected from Feb, 1997 to Aug, 2010 in the Department of Dermatology, Sun Yet-sen Memorial Hospital. Results Among the 241 cases, 179 (74.27%) were tinea alba, 34 (14.11%) tinea kerion, 28 (11.62%) black dot ringworm, and no favus was observed. The dominant pathogenic fungi in decreasing order were Microsporum canis (182,80.89%), Trichophyton violaceum (25, 11.11%), Trichophyton mentagrophytes (10, 4.44%), Trichophyton tonsurans (3, 1.33%), Trichophyton rubrum (2, 0.89%), Microsporum gypseum (2, 0.89%) and Trichophyton verrucosum (1, 0.44%). Children were the main population (39.00%) suffering from tinea capitis. Conclusions In Guangzhou region, tinea alba is the most common type of tinea capitis, Microsporum canis is the main causative pathogen, and children are the predominate population affected by tinea capitis.

Black-dot ringworm caused by Trichophyton tonsurans and analysis of its extracellular enzymatic activity

Objective To report a case of black-dot ringworm caused by Trichophyton tonsurans in a 3-year-old girl. Methods Lesional hair was obtained from the patient and subjected to direct microscopic examination as well as culture. Subsequently, the isolate underwent morphological, biochemical and molecular biology identification. The extracellular enzymatic activity of the isolate was analyzed. Results Microscopy revealed that the hair shaft was filled with fungal spores. Typical colony of the isolate was grayish-white with downy appearance. Slide culture showed centipede-like, lateral, rod-shaped microconidia. Urease test was positive. The amplification of ribosomal DNA (rDNA) ITS domains by PCR produced a 687 bp-sized fragment which had a 100% homology with the sequences of several Trichophyton tonsurans strains in the GenBank database. The extracellular enzymatic activity analysis showed an increase in the activity of alkaline phos-phatase, acid phosphatase, esterase (C4), β-glucosidase, leucine arylamidase, N-acetyl-β-glucosaminidase and a-mannosidase. Conclusions The pathogenic fungus is identified as Trichophyton tonsurans based on morphological and biochemical features as well as sequence of the ITS region of rDNA, and the child was diagnosed with black-dot ringworm. Key words: Tinea; Trichophyton tonsurans; Laboratory techniques and procedures

Ｔｒｉｃｈｏｐｈｙｔｏｎ ｔｏｎｓｕｒａｎｓによる右前腕のｂｌａｃｋ ｄｏｔ ｒｉｎｇｗｏｒｍ

We report a case of black dot ringworm on the right forearm caused by Trichophyton (T.) tonsurans. A 16-year-old male high school Judo-wrestler visited our clinic on September 30, 2005, complaining of a round erythematosquamous eruption with a distinct margin on the right forearm. Black dots were observed in the lesion. KOH-Parker ink prepared direct microscopy revealed abundant large endotrix arthroconidia in the hair shaft. Culture yielded yellowish-brown colonies. The isolate produced numerous round, short club-shaped microconidia along the hyphae unstained with lactophenol cotton blue (resembling matchsticks) and chlamydospores. PCR-RFLP analysis of internal transcribed spacer regions of ribosomal DNA revealed a banding pattern compatible with T. tonsurans. The lesion was cured by daily administration of 125 mg of terbinafine for 13 weeks.

A Chinese–Japanese boy with black dot ringworm due to Trichophyton violaceum

A 4-year and 8-month-old Chinese-Japanese boy, who had been visiting Dalian, China frequently, developed multiple alopecia lesions 1 year previously. At his initial visit to our department, multiple patchy alopecia with black dots was observed in the parietal scalp area. Multiple erythematous macules were also seen on the face, nape and right dorsum of the hand. A diagnosis of tinea capitis and tinea corporis was obtained on the basis of potassium hydroxide (KOH) microscopic examination of hair and scales from the lesions. Colonies grown on Sabouraud cycloheximide-chloramphenicol agar culture were examined using Fungi-Tape and MycoPerm-blue, and numerous microconidia and a small number of macroconidia were observed. Trichophyton violaceum was identified as the causative organism on the basis of colony morphology, microscopic morphology and molecular biology technique. As T. violaceum infection is not often seen in Japan, we suspected that the patient was infected by T. violaceum during his stay in Dalian. Conidia formation is rarely observed with T. violaceum, and only five cases with T. violaceum macroconidia formation have been reported in Japan (including this case). We also report the method for visualizing conidia formation of T. violaceum using Fungi-tape and MycoPerm-blue.

Les teignes à madagascar : enquête dans une école d’Antsirabé

Tinea capitis is a common infection among schoolchildren in developing countries. This condition is still under-reported in Madagascar. In order to assess the prevalence of Tinea capitis in Madagascar, we conducted a study in a primary school in Antsirabe, a town located in the country's high central territories. Samples were taken from 210 children in the 4 school classes aged between 6 and 14 years. Only children with scaling lesions or with alopecia were sampled. No microsporic gray-patch ringworm was found in any of the children. Samples were obtained from a total of 83 children. Cotton swabs moistened with distilled sterilized water were rubbed on the children's scalps for 15 seconds and the scales thus collected were then seeded on 2 separate tubes of Sabouraud-Dextrose-Agar media containing chloramphenicol, one with and the other without cycloheximide. The tubes were incubated at a temperature of 27 degrees C for 4 weeks. All the micromycetes were identified (dermatophytes, yeasts and molds). Three species of dermatophytes were isolated: one anthropophilic species, responsible for black-dot ringworm (Trichophyton tonsurans), and 2 geophilic dermatophytes, unusual in human disease (Microsporum boullardii and Trichophyton terrestre). Of the 83 children sampled, 17 had 20 dermatophytes (in 3 children, 2 different species of dermatophytes were associated). We collected 15 Trichophyton tonsurans (2 Trichophyton tonsurans were associated with Microsporum boullardii, and 1 with Trichophyton terrestre), and 2 Microsporum boullardii. The prevalence of carriers of dermatophytes was 8 p. 100 for all children and 20.5% for the sampled children. Children in Madagascar, unlike those in Central Africa, do not develop microsporic gray-patch ringworm caused by Microsporum langeronii. However, they may present tinea capitis with small alopecic lesions, or they may frequently have Trichophyton tonsurans and seem to have healthy scalps. In contrast with Central Africa, where T. soudanense is the main cause of black-dot ringworm, and with North Africa, where T. violaceum is most frequently seen, these 2 species are not found in Antsirabe. Studies carried out in coastal regions with a more tropical climate could perhaps show other dermatophytes responsible for tinea capitis. Anthropophilic tinea capitis caused by Trichophyton tonsurans is endemic in the Antsirabe area. The lesions are inconspicuous with diffuse scaling, like those reported in surveys conducted in the USA. Mycological investigation followed up by topical treatment with a fungicide could diminish the spread of this anthropophilic, and thus contagious, dermatophyte. Trichophyton tonsurans has also reappeared regularly in France over the past few years.

老人ホーム入居者および職員にみられたＴｒｉｃｈｏｐｈｙｔｏｎ ｖｉｏｌａｃｅｕｍ感染症

Six cases of Trichophyton (T.) violaceum infection seen in a nursing home are reported. A 66-year-old female (case 1) was found with tinea corporis on her face, chest and shoulder, associated with black dot ringworm. A KOH examination of hair showed endothrix parasitism. Reddish purple colonies were isolated from the patient on Sabouraud's dextrose agar, and intercalary and terminal chlamydospores were observed on slide culture. PCR-RFLP analysis of the microorganism showed a pattern of T. violaceum type. Therefore, the isolated fungus was identified as T. violaceum, a typical anthropophilic dermatophyte which had spread among residents and staffs easily. Using a mycological method, we examined 59 persons (21 residents and 38 staff members) who had had contact with case 1. The results were as follows. An 85-year-old female (case 2) and an 83-year-old female (case 3) were carriers of T. violaceum. A 23-year-old male (case 4) had tinea corporis on his right forearm due to T. violaceum. A 24-year-old male (case 5) probably had tinea corporis on his right forearm due to T. violaceum. One year after case 1's first visit to our clinic, we observed an 88-year-old female (case 6) of tinea capitis by T. violaceum. It seems that the organism was preserved in surroundings and members of the nursing home. The contagion in our cases could either have been caused by directly touching the person or by sharing their comb. PCR-RFLP analysis was performed within a short time, so that we managed effectively to select a way of treatment and to prevent the infection from spreading.

Molecular confirmation of a Trichophyton violaceum isolate from human black-dot ringworm.

A clinical isolate from a black-dot ringworm lesion of a 28-year-old female Japanese was investigated by morphological and biochemical analyses as well as molecular analyses. The isolate grew well on thiamine enriched agar and did not produce violet pigment, macro-conidia or micro-conidia on Sabouraud's dextrose agar. Approximately 620-bp genomic DNA fragments of the CHS1 gene were amplified from Trichophyton mentagrophytes, T. rubrum, T. tonsurans and T. violaceum by polymerase chain reaction (PCR) and sequenced. The chitin synthase 1 (CHS1) nucleotide sequences of the clinical isolate showed more than 97% similarity to that of T. violaceum and less than 96% similarity to that of T. mentagrophytes, T. rubrum and T. tonsurans. The phylogenetic analysis of their sequences revealed that the clinical isolate was genetically close to T. violaceum and distinct from T. mentagrophytes, T. rubrum and T. tonsurans. Therefore, the isolate was confirmed as T. violaceum by mycological examination and molecular analyses.

Tinea Capitis in Adults in Southern Taiwan

We report the clinicomycologic study of 27 culture-proven cases of tinea capitis from southern Taiwan during the years 1988 to 1990. The series is notable for its predominance of adults (63%), of women (89%), and of Trichophyton violaceum infection (74%). The age distribution was clearly bimodal; the median age was 6 years for children and 56 years for adults (older than 18 years). Whether or not these findings represent a new trend of tinea capitis in southern Taiwan remains to be determined. Clinically, our cases of black-dot ringworm caused by T. violaceum often presented with subtle changes of scaling, hair loss, and black dots. The keys to the correct diagnosis are (1) a high clinical index of suspicion with careful inspection of the scalp for the presence of black dots, and (2) microscopic examination and culturing of the black dots or plucked hairs.

Fungus Invasion into Human Hair Tissue in Black Dot Ringworm: Light and Electron Microscopic Study

In order to investigate the morphology of fungi invading into the human hair tissue, three cases of black dot ringworm caused by Trichophyton violaceum and Trichophyton glabrum were studied by light and electron microscopy. Fungal elements were mainly present in the hair cortex and showed a constant morphologic change during the differentiation of hair layers. The fungal elements, located deep in the keratogenous zone of the cortex, showed less electron dense non-septate hyphae. Distally, the hyphae showed septation and contained several scattered dense bodies in the cytoplasm. At the level where the Huxley's layer was keratinized, the fungal elements were transformed into arthrospores, which occupied the large volume of the cortex; each spore was surrounded by a fiber- and melanosome-free, electron lucent halo. Fungal elements occasionally invaded the keratinized hair cuticle and keratinized inner root sheath in a few hair follicles. Fungi do not invade the hair germinative cells. There seems to be a distinct relationship between the morphology of the invading fungi and the cortical cell differentiation in black dot ringworm; a balance between the fungus proliferation and the cortical cell development may be present.

Two Cases of Kerion Celsi Report of our cases and statistical observation of kerion celsi, tinea capitis superficialis and black dot ringworm in the Japanese literatures during the past five years (1981-1985).

Two Cases of Kerion Celsi Report of our cases and statistical observation of kerion celsi, tinea capitis superficialis and black dot ringworm in the Japanese literatures during the past five years (1981-1985).

The most common type of fractured hair in alopecia areata in children: another cause of "black dot disease".

SummaryExclamation mark hairs are usually described as the typical type of fractured hair in alopecia areata, but hairs that are fractured close to the scalp are more common in alopecia areata in children. They appear as black dots, similar to those seen in black dot ringworm. The only specific reference to this condition that was found in 40 text books of dermatology is in a book published in 1906.

Trichophytin Reactions in Children With Tinea Capitis

Of 52 patients with proved Trichophyton tonsurans infection of the scalp, 16 had an inflammatory reaction to this infection (kerion), while the rest had only slight scaling and broken hairs (black dot ring-worm). Each patient was tested with trichophytin antigen to determine whether cell-mediated immunity (CMI) was responsible for the differences in these different clinical presentations. Fifteen of 16 with kerion had a 48-hour reaction greater than 10 mm, while none of the 36 with noninflammatory (black dot) tinea capitis had a similar response. This suggests that the patient's immune response (CMI) may be responsible for kerion infections of the scalp and that therapy could be directed initially toward suppressing this reaction.

Black dot tinea capitis caused by Trichophyton rubrum.

An unusual case of tinea capitis due to Trichophyton rubrum in an adult woman is described. The scalp showed typical black dot ringworm; microscopically, a large-spore endothrix fungus was seen. The scalp lesions responded rapidly to griseofulvin.

Hyphal Fusion between Trichophyton tonsurans Variants as an Indication of Species Relationship

Until recently the crateriform group of Trichophytons was consid? ered to contain four species: P. tonsurans or crateriforme, P. epilans or cerebriforme, P. Sabouraudii or acuminatum, and P. sulfureum (Conant et al., 1945). In 1944 Carrion and Silva suggested inclusion of the three first-named species into one species, P. tonsurans, and retaining P. sulfureum as a second species in this group. Gonzalez Ochoa and Vasquez in 1945 proposed the establishment of a single species, P. tonsurans, with the varieties epilans, Sabouraudii, and sulfureum, and this proposal has now been generally adopted (Conant et al, 1954). The clinical manifestations of P. tonsurans infection were recently summed up by Reiss (1954). All four variants of the species cause endothrix tinea capitis. The clinical condition may be that of Black Dot ringworm, often resembling diffuse alopecia, or acute inflammatory reactions and even kerion may be seen. Cultures obtained from these conditions are extremely variable in their gross appearance. The colonies may present a heaped-up, acumi? nate center (var. Sabouraudii), or the center may be sunken, crateri? form (var. tonsurans). The surface may be irregularly convoluted, cerebriform (var. epilans). The color of the aerial mycelium may be white, cream, primrose, rose, or sulfur yellow (var. sulfureum). The texture may be powdery or velvety. A red pigment may be present on the reverse of the colony. Microscopically all these variants show close resemblance. They present pyriform or elongated, sometimes two-celled, microconidia ar-