| Tinea Versicolor (TV) is one of the most common diseases in summer. The pathogen of this disease is Malassezia, a fungi genus which can also be identified in the normal skin in human. It is often represented hypopigmentation and hyperpigmentation in the regions of lesion during eruption and after cure, which may not disappear for months or even years. Therefore, it is of importance to investigate the factors and mechanism that cause pigmentation in TV. In the present study, we have isolated and identified M. species in tissues obtained from the lesions and normal skin on the back and upper arms of the patients suffered from TV, and compared the constitution of M. species between lesions of hypopigmentation and hyperpigmentation, and between infectious and normal skin.MethodWe have investigated 108 outpatients with PV of our department during 2002.7 ~ 2002. 10,. Entrance criterion: the patients have typical clinical features such as scaly to nail - sized macular lesions with clear - cut boundaries. The colors of lesions may be classified as hypopigmented, hyperpigmented, leu-koderma or erythematous. M. species are positive by direct microscopic test. Exclusive criterion: the patients who treated with topical or oral antifungal medication.Samples were scraped from the lesions and normal skin of back and upper arm of patients by and inoculated on Leeming and Nortman agar (the distance between samples from infectious tissue and normal skin is more than 3 cm) for culture. After 7 ~ 14 days, we confirmed it as the first generation of mslassezia species by 50% Parker ink dye under microscope, and isolated single colony onthe same culture medium for preservation.The strains were differetiated by the morphology, catalase test, and the growth ability in presence of Tween20, Tween 40 Tween 60 , Tween80 and PEG -35, following protocals established by Guillot, et al. M. globosa and M. obtu-sa are the only M. species can be identified by their morphology alone. The i-dentification of the species was confirmed on standard strains of the fungi, kindly bestowed by Professor Liu Weida from Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical college.Results1. Identification and isolation of M. species from lesions, normal back and upper armsM. globosa was isolated in 63 patients (57. 8% ) , and was the only strain identified in 51 cases among these patients. Within other 12 cases, M. globosa was isolated in association with either M. Sympodialis (10 cases) orM. Furfur (2 cases). M. Sympodialis was isolated in 41 patients (37. 6% ), and was the only strain found in 28 cases. Within other 13 cases, it is isolated in association with either M. globosa or M. Furfur . M. Furfur was found alone in 10 cases, and associated with M. slooffiae in 2. M. obtusa was found alone in 1 case and M. resticta in 2.2. Constitution of M. species isolated from lesions with different colorIn 108 patients, 48 showed hyperpigmented and45 showed hypopigmented. Hyperpigmented mixed with hypopigmented in 9 cases and with erythematous in 2. Erythematous in mixture with hyperpigmented in 4 cases.3. The relationship between course and pigment alterationAmong the patients we investigated, the shortest course was 3 days and the longest was 20 years. The mean course of the patients with hypopigmentation or hyperpigmentation are 17.33 +6.91months and 14.23 +5.73months.ConclusionsThe major strains of malassezia in tinea versicolor are M. globosa and M.sympodialis in Zhejiang Province in China. However, lesions showing hypopig-mentation or hyperpigmentation in tinea versicolor are irrelevant to strains of the genera, neither are they relevant to the courses of the disease.
|
PDF Full Text Request