Mark Ming-Long Hsu

Demodicosis: A clinicopathological study

BACKGROUND Demodex mites are common commensal organisms of the pilosebaceous unit in human beings and have been implicated in pityriasis folliculorum, rosacea-like demodicosis, and demodicosis gravis. OBJECTIVE We sought to describe the spectrum of clinicopathological findings and therapeutic responses of demodicosis in Taiwanese patients. METHODS We conducted a retrospective study to review clinicopathologic findings and therapeutic responses of 34 cases of diagnosed demodicosis. RESULTS Fifteen cases with positive results of potassium hydroxide examination, standardized skin surface biopsy specimen, and/or skin biopsy specimen, and resolution of skin lesions after anti-Demodex treatment were included for final analysis. Nineteen cases were excluded because of insufficient positive data to make a definite diagnosis. There were 4 male and 11 female patients (age 1-64 years, mean age 38.7 years). The disease was recurrent or chronic with a duration ranging from 2 months to 5 years (mean 15.7 months). The skin lesions were acne rosacea-like (n = 8), perioral dermatitis-like (n = 5), granulomatous rosacea-like (n = 1), and pityriasis folliculorum (n = 1). Skin biopsy was performed in 7 patients. Overall, the histopathology was characterized by: (1) dense perivascular and perifollicular lymphohistiocytic infiltrates, often with abundant neutrophils and occasionally with multinucleated histiocytes; (2) excessive Demodex mites in follicular infundibula; and (3) infundibular pustules containing mites or mites in perifollicular inflammatory infiltrate. The skin lesions resolved after treatment including systemic metronidazole, topical metronidazole, crotamiton, or gamma benzene hexachloride. LIMITATIONS Small sample size and a fraction of patients without long-term follow-up are limitations. CONCLUSION Demodicosis should be considered in the differential diagnosis of recurrent or recalcitrant rosacea-like, granulomatous rosacea-like, and perioral dermatitis-like eruptions of the face. Potassium hydroxide examination, standardized skin surface biopsy, skin biopsy, or a combination of these are essential to establish the diagnosis.

Identification of dermatophytes by sequence analysis of the rRNA gene internal transcribed spacer regions

Identification of dermatophytes using the traditional method is sometimes problematic because of atypical microscopic or macroscopic morphology. The aim of this study was to evaluate the feasibility of using sequencing of the ribosomal internal transcribed spacer (ITS)1 and ITS2 regions for identification of 17 dermatophyte species. The ITS regions of 188 strains (62 reference strains and 126 clinical isolates) were amplified by PCR and sequenced. Species identification was made by sequence comparison with an in-house database comprising ITS sequences of type or neotype strains or by blast searches for homologous sequences in public databases. Strains producing discrepant results between conventional methods and ITS sequence analysis were analysed further by sequencing the D1-D2 domain of the large-subunit rRNA gene for species clarification. The identification rates by ITS1 and ITS2 sequencing were higher than 97 %. Based on reference sequences of type or neotype strains, it was noted that most strains of Trichophyton mentagrophytes were misidentifications of Trichophyton interdigitale. In addition, barcode sequences were present in species of the Microsporum canis complex and Trichophyton rubrum complex. These barcode sequences are useful for species delineation when the results of ITS sequencing are ambiguous. In conclusion, ITS sequencing provides a very accurate and useful method for the identification of dermatophytes.

Identification of Dermatophytes by an Oligonucleotide Array

ABSTRACT Species of dermatophytes are classified into three anamorphic (asexual) genera, Epidermophyton, Microsporum, and Trichophyton. Conventional methods used to identify dermatophytes are often lengthy and may be inconclusive because of atypical microscopic or colony morphology. Based on the internal transcribed spacer 1 (ITS-1) and ITS-2 sequences of the rRNA genes, an oligonucleotide array was developed to identify 17 dermatophyte species. The method consisted of PCR amplification of the ITS regions using universal primers, followed by hybridization of the digoxigenin-labeled PCR products to an array of oligonucleotides (17- to 30-mers) immobilized on a nylon membrane. Of 198 dermatophyte strains and 90 nontarget strains tested, the sensitivity and specificity of the array were 99.5% and 97.8%, respectively. The only strain not identified (Microsporum audouinii LMA 597) was found to have a nucleotide insertion at the ITS-2 region where the probe was designed. Two nontarget strains, Microsporum equinum LMA 40396666 and Trichophyton gourvilii var. intermedium CBS 170.65, were misidentified as Microsporum canis and Trichophyton soudanense, respectively. Sequence analysis of the ITS regions revealed that the two misidentified strains displayed high sequence homology with the probes designed for M. canis and T. soudanense, respectively. The present method can be used as a reliable alternative to conventional identification methods and can be completed with isolated colonies within 24 h.

Prevalence of Skin Diseases Among Schoolchildren in Magong, Penghu, Taiwan: A Community-based Clinical Survey

BACKGROUND/PURPOSE Skin diseases are common in children. Epidemiologic studies of skin diseases in schoolchildren performed by direct inspection by dermatologists are limited in Taiwan. The current study surveyed the prevalence of selected childhood dermatoses in Magong City, Penghu, the largest offshore island of Taiwan. METHODS A cross-sectional study was carried out in June 2005, in which a total of 3273 children aged 6-11 years living in Magong were examined by at least two board-certified dermatologists, with regard to the point prevalence of acne, ephelides, atopic dermatitis, warts, keloids, vitiligo, fungal infections, alopecia areata and psoriasis. The skin of the scalp, face, neck, trunk and extremities were inspected; that of the breast, genitalia and feet were skipped for privacy. RESULTS Acne vulgaris was found at the age of 7 in both genders, with comedones being the earliest manifestation. The overall prevalence of acne was 17.3% (95% CI, 16-18.6%). Ephelides were frequently observed in the children (prevalence rate, 15.24%; 95% CI, 14-16.47%). The prevalence of atopic dermatitis was 4.33% (95% CI, 3.63-5.03%), with more boys affected than girls (1.49:1) (p = 0.03). The prevalence of warts on the hands was 2.81% (95% CI, 2.24-3.38%). Keloids were identified in seven boys and four girls, accounting for 0.33% of the children (95% CI, 0.13-0.53%). Three children had vitiligo (prevalence rate, 0.09%; 95% CI, 0-0.19%). The prevalence of fungal infection including tinea nigra, tinea versicolor and tinea corporis was 0.24% (95% CI, 0.07-0.41%). Neither alopecia areata nor psoriasis was identified. CONCLUSION Compared with our previous study in Kaohsiung County using similar methodology, the point prevalence of atopic dermatitis and ephelides was significantly higher whereas that of fungal infection was lower in Penghu. Unexpectedly, tinea nigra was not rare in Penghu.

Follow‐up of skin manifestations in Yu‐Cheng children

We report an 11‐year follow‐up study on the dermatological manifestations of Yu‐Cheng children born to mothers who were poisoned by polychlorinated biphenyl (PCB)‐contaminated cooking oil between 1977 and 1979. Eighty‐eight children born to these mothers, and 86 matched controls, were examined by one dermatologist. Chloracne scars were found in one patient, and there were nail abnormalities in about one‐third of the exposed patients. Transverse grooves, irregular depressions, and koilonychia/nail flattening were significantly more frequent than in the control group, based on Fischers exact test. This study indicates that in Yu‐Cheng children the nail changes are the most persistent abnormality after PCB intoxication, and their occurrence may indicate developmental retardation of the fetal nail matrix. Such a finding might also suggest that PCBs remaining in the mother could exert an effect on nail growth in children born several years after the intoxication event.

Serotypes and mating types of clinical strains of Cryptococcus neoformans isolated in Taiwan

Twenty-one strains ofCryptococcus neoformans isolated from patients in Taiwan were characterized for serotypes and mating types. Slide agglutination test was performed with 8 factor-specific sera (Iatron Company, Japan) to determine the serotypes. Wheat bran agar (WBA) and malt extract agar (MEA, Wickerham) media were used for the mating tests. Twenty of the isolates were of serotype A, and one was serotype B. Except for 2 strains of serotype A, all of the serotype A strains mated withFilobasidiella neoformans var.neoformans, mating type a. The only serotype B strain mated withF. neoformans var.bacillispora mating type a in MEA medium. These data revealed the low prevalence (1/21; 4.8%) ofC. neoformans var.gattii in Taiwan, a subtropically located island.

Coexistence of three variants of porokeratosis with multiple squamous cell carcinomas arising from lesions of giant hyperkeratotic porokeratosis

JEADV 2006, 18, 602–634

High-frequency intragenomic heterogeneity of the ribosomal DNA intergenic spacer region in Trichophyton violaceum.

ABSTRACT The intergenic spacer (IGS) of the rRNA genes was analyzed from the dermatophyte Trichophyton violaceum isolated from cases of tinea capitis in Taiwan and Iran. T. violaceum strains were cultured from different colonies, from single conidial colonies derived by dilution plating, and from micromanipulation of single conidia from clinical samples. A ribosomal DNA probe hybridizing to multiple EcoRI fragments was used to compare restriction fragment length polymorphisms in different T. violaceum isolates. The arthroconidia of T. violaceum that form in vivo during infection were shown to contain a single nucleus by 4′,6′-diamidino-2-phenylindole staining. IGS regions from an isolate cultured from a single conidium were amplified, cloned, and sequenced. The results identified that heterogeneity exists between IGS regions within a single T. violaceum genome due to different copy numbers of a 171-bp tandem repeat. This suggests that the IGS of T. violaceum is partially excluded from the concerted evolution of the rRNA gene locus. The heterogeneous character of the IGS regions in T. violaceum contrasts with the closely related dermatophyte Trichophyton rubrum, posing further questions on the phylogeny and the evolution of dermatophyte fungi.

A novel splice mutation in the ATP2C1 gene in a woman with concomitant psoriasis vulgaris and disseminated Hailey-Hailey disease.

Concurrent psoriasis vulgaris and Hailey–Hailey disease is very rare. The clinical and pathologic findings of widespread Hailey–Hailey disease in a 48‐year‐old woman with pre‐existing generalized psoriasis vulgaris were described. In our patient, the vesicular eruption of Hailey–Hailey disease was obscured clinically by the psoriatic lesions. The diagnosis of both diseases was confirmed pathologically. The patient had a total of five skin biopsies performed over the neck, flank area, back, pubic area, and a finger. Acantholytic dyskeratosis, changes suggestive of Hailey–Hailey disease, were found in four specimens, psoriasis in two specimens, and both diseases in one specimen. The diagnosis of Hailey–Hailey disease was further confirmed by detecting a novel splice mutation (832G>A) in the ATP2C1 gene. Our case illustrated that diagnosis of disseminated Hailey–Hailey disease may easily be missed in a patient with a pre‐existing generalized pruritic eruption, such as psoriasis. The appearance of eczematous vesicular eruption or eroded intertrigo‐like lesions in a patient with pre‐existing generalized eruption should raise a suspicion of Hailey–Hailey disease.

Rapid detection of dermatophytes and Candida albicans in onychomycosis specimens by an oligonucleotide array.

BackgroundOnychomycosis is a fungal infection of nails, leading to the gradual destruction of the nail plate. Treatment of onychomycosis may need long-time oral antifungal therapy that can have potential side effects, thus accurate diagnosis of the disease before treatment is important. Culture for diagnosis of onychomycosis is time-consuming and has high false-negative rates. To expedite the diagnosis, an oligonucleotide array, based on hybridization between immobilized oligonucleotide probes and PCR products, for direct detection of dermatophytes and Candida albicans in clinical specimens was evaluated.MethodsSpecies-specific oligonucleotide probes designed from the internal transcribed spacer (ITS) regions of the rRNA gene were immobilized on a nylon membrane. The assay procedures consisted of PCR amplification of the ITS using universal primers, followed by hybridization of the digoxigenin-labeled amplicons to probes on the array. Thirty two nail samples (29 patients) were analyzed by the array, and the results were compared with those obtained by culture. Array-positive but culture-negative samples were confirmed by cloning and re-sequencing of the amplified ITS and by reviewing patient’s clinical data. The total recovery of culture and confirmed array-positive but culture-negative results was considered 100% and was used for performance evaluation of both methods.ResultsConcordant results were obtained in 21 samples (10 positives and 11 negatives) by both methods. Eleven samples were array-positive but culture-negative; among them, 9 samples were considered true positives after discrepant analysis. Comparing with culture, the array had significantly higher sensitivity [100% (95% CI 82.2% −100%) vs 52.6% (28.9% −75.5%), p <0.001] and negative predictive value [100% (71.3% −100%) vs 59.1% (36.4% −79.3%), p <0.05), while no significant differences were observed in specificity (84.6% vs 100%, p =0.48) and positive predictive value (90.5% vs 100%, p =1.0). The whole procedures of the array were about 24 h, whilst results from culture take 1 to 3 weeks.ConclusionsThe array offers an accurate and rapid alternative to culture. Rapid diagnosis can expedite appropriate antifungal treatment of onychomycosis. However, the single site nature of this study conducted at a referral hospital invites caution.