CHAPTER 15
FUNGAL INFECTION OF THE SKIN
（皮膚真菌症）
I. Dermatophyte Infection
・Classification: superficial and deep dermatophytoses.
・Generation: Three principal genera: Microsporum（小胞子菌）, Trichophyton（白癬菌）, Epidermophyton（表皮菌）.
A. Superficial Trichophytosis（表在性糸状菌症）
1. Tinea Capitis（頭部白癬）: more common in children,Brittle hair,erythematous patch with scales.
2. Tinea Corporis（体部白癬）: all ages. small-to-large, scaling, sharp margined erythematous plaques with central healing.
3. Tinea Pedis（足白癬）: scaling, maceratin on interdigital spaces, erythema and vesicles on sales and hyperkeratosis of keratin.
B. Deep Trichophytosis（深在性糸状菌症）
1. Kerion celsi（ケルスス禿瘡）: Boggy, elevated, purulent, inflamed nodules and plaques on the scalp, which are extremely painful and drain pus. Heal with scarring alopecia.
2. Tinea barbae（白癬性毛瘡）: adult male only. Pusutular folliculitis,hair follicle surrounded by red papules or pustules. With less follicular involvement, there are scaling circular, reddish patches in which hair is broken off at the surface. Kerion formation may occur.
Diagnosis
Direct microscopic examination of hyphae on KOH skin or nail scraping specimen
Treatment
topical antifungal ointment. In Kerion and severe form of Tinea barbae, antibiotics for accompanying bacterial infection, and terbinafine or itraconazole should be given.
II. Mucocutaneous Candidiasis（皮膚粘膜カンジダ症）
・Superficial mycotic infection (Candidia albicans, C. tropicalis) occurring on moist cutaneous sites mucosal surfaces.
・Most patients have predisposing factors that alter local immunity, such as increased moisture at the site of infection, diabetes, antibody therapy, or alteration in systemic immunity.
A. Vulvovaginitis（外陰・膣カンジダ症）
Thick creamy white, curdy discharge, meaty-red erythema of vaginal skin and mucosa.
Spreads to perineum and groin. Satellite pustules.
B. Diaper Candidiasis（乳児寄生菌性紅斑）
Well defined erythema with scales, and occasionally papular and pustular lesions involving perigenital and perianal skin, medial aspect of thighs, and buttocks.
C. Interdigital and Intertriginous Candidiasis（カンジダ性間擦疹）
Sharply demarcated erythematous, erosive lesions with macerated scules, and occasional pustule formation at the periphery. Inter digital, submammary, groin and scrotum.
D. Follicular candidiasis（カンジダ性毛のう炎）
・Small, discrete pustules with or without erythema.
Diagnosis
Direct microscopic examination of skin or nucosal scraping, or of pus using KOH preparation
III. Pityriasis Versicolor（癜風）
・A chronic asymptomatic superficial fungal (Malassegia furfur) infection of the trunk, characterized by white or light brown, scaling macules.
Diagnosis
Direct microscopic examination of scales, hyphae and spores referred to as "spaghetti and meat-balls" appearance.
Treatment
topical application of Miconazole cream...etc.
IV. Deep Fungal Infection（深在性真症）
A. Sporotrichosis
・A cutaneous localized mycotic (Sporotrix schenckii, a dimorphic: hyphae and yeast form found in soil) infection which follows accidental inoculation of the skin.
・Characterized by nodule and ulcer formation at the inoculation site, chronic nodular lymphangitis, and regional lymphademitis.
・Primary lesion: common on dorsal hand and fingers.
1. Local Cutaneous Type (chancriform) (40%)（限局性皮膚型）
a. Papule, pustule, or subcutaneous nodule appears at inoculation site several weeks after wound, becoming fixed to deeper tissues.
b. Painless indurated ulcer occurs (sporotricoid chancre).
c. Draining lymph node: swelling.
2. Chronic Lymphangitic Type (Sporotrichoid) (60%)（皮膚・リンパ管型）
a. Follows lymphatic extension of local cutaneous type; proximal-to-local cutaneous lesion, intervening lymphatics become indurated, noduler, thickened.
B. Fixed Cutaneous Sporotrichosis（皮膚固定型スポロトリコーシス）
Crusted ulcers, ecthymatous, verrucous plaques or nodule
General Examination
Hematogeneous dissemination (rare); bone, muscle, joint, visceral, CNS lesion.
Diagnosis
Clinical suspicion and isolation of organism on culture
Histology
Non specific inflammatory granuloma. Asteroid body（星芒体）can be found characteristically.
Treatment
Oral administration of KI (1g/day several weeks). Amphotericin B I. V., for those with pulmonary or disseminated infection. Alternative: ketoconazole.
C. Chromomycosis（黒色負菌症）
・Chronic dermatosis caused by dermatiacious fungi (Fonsecaea pedrosoi, Exophiala dermatitidis, Phialophora verrucosa) infection via minor trauma.
Course and Skin Lesions
1. It begins as a small ecthymatous papule or warty nodule, as a rule on some parts of the foot, spreading by growth of satellite lesions.
2. Plaque-like and cicatrical types of lesions also occur, the cicatrical type is formed by nodules and spread peripherally; healing with sclerosis and scar formation.
3. Adenitis as a result of bacterial complication may occur.
4. Spread of the lesion is very slow; many years to develop fully.
5. Systemic involvement is rare, but metastasis through the blood stream can be occur (to brain, lung...etc.)
6. There have been cases of mild pulmonary involvement and the pulmonary portal of entry has been considered in addition to the local inoculation infection of the skin.
Diagnosis
Mcroscopic examination of scales or pus and lesional fissure: sclerotic cells
Culture: isolation of the fungi
Histology
Pseudcarcinomatous hyperplasia of the epidermis. Inflammatory granuloma with fungus elements including sclerotic cells.
Treatment
Excision and skin grafting. Systemic administration of antifungal drugs.