LECTURE 1 dr. Sisi

Cards (65)

  • Main learning objectives
    • To list and identify the common dermatophytes causes fungal cutaneous and subcutaneous infection
    • To describe the pathology and clinical presentation of fungal infection of the skin, nail, hair, and subcutaneous
    • To choose the simple method of fungal laboratory investigation for clinical specimen
    • To name the drug of choice for the treatment of each infection
    • To aware with the transmission and epidemiology of these infections
  • Mycoses: diseases cause by fungi
  • Types of mycoses
    • Cutaneous
    • Subcutaneous
    • Systemic: Endemic, Opportunistic
  • Cutaneous mycoses
    • Affect the dead layer of skin, epidermis, hair, nails
    • Representative diseases: Tinea-versicolor, Dermatophytosis
    • Causative organisms: Malassezia, Microsporum, Trichophyton, Epidermophyton
  • Subcutaneous mycoses
    • Affect the subcutis
    • Representative diseases: Mycetoma, Sporotrichosis
    • Causative organisms: Several genera, Sporothrix
  • Opportunistic mycoses
    • Affect internal organs
    • Representative diseases: Candidiasis, Aspergillosis, Cryptococcosis, Mucormycosis
    • Causative organisms: Candida, Aspergillus, Cryptococcus, Mucor, Rhizopus
  • Systemic mycoses
    • Affect internal organs
    • Representative diseases: Histoplasmosis, Blastomycosis, Coccidioidomycosis, Paracoccidioidomycosis
    • Causative organisms: Histoplasma, Blastomyces, Coccidioides, Paracoccidioides
  • Fungal infection has emerged as a worldwide health-care problem in the last decade
  • Why care about fungal infections?
    • Fungi are a leading cause of nosocomial infections
    • Fungal infections are a major problem in immune suppressed people
    • Fungal infections are often mistaken for bacterial infections, with fatal consequences
  • Superficial mycosis is still ranked as one of top infectious skin diseases in Indonesia
  • In the last 3-5 years, among the various superficial mycosis, dermatophytoses was the most frequent type reported, followed by pityriasis versicolor and candidosis
  • A recent epidemiologic survey in a rural area in Java showed that pityriasis versicolor was the most frequent finding, and tinea was more frequently found located on the body
  • Cutaneous mycoses: Dermatophytoses (Ringworm/Tinea)
    • Caused by Dermatophytes (Trichophyton, Microsporum, Epidermophyton)
    • Transmitted by direct contact with skin scales
  • Dermatophytoses only infect superficial keratinized structures (skin, hair, nails), not deeper tissues
  • Types of dermatophytoses
    • Tinea capitis
    • Tinea corporis
    • Tinea cruris
    • Tinea pedis
    • Tinea unguium
    • Tinea favosa
    • Tinea barbae
    • Tinea imbricata
  • Tinea cruris was the major type of dermatophytoses, exceeding tinea corporis
  • Tinea capitis showed a decline in frequency, but tinea unguium and onychomycosis were more frequent
  • Tinea imbrikata was only reported from Manado and Papua
  • There was an increasing report of unusual and widespread clinical findings of dermatophytoses in immunocompromised individuals
  • Dermatophytoses
    • Chronic infection in warm, humid areas of the body
    • Typical ringworm lesions with inflamed circular border, papules, vesicles, and clear central area
    • Broken hairs
    • Thickened broken nails
  • Dermatophytes are molds that use keratin as a nutritional source, not dimorphic, and their habitat is mainly human skin (except Microsporum canis which infects dogs and cats)
  • Ringworm infection
    • On cat
    • On human skin
  • Tinea capitis
    • Dermatophytosis of the scalp hair follicle, caused by Microsporum and Trichophyton
    • Clinical findings: black dot, gray patch, scaling patches of alopecia with broken hairs
  • Tinea corporis
    • Dermatophytosis of the glabrous skin of the face, trunks, and limbs
    • Synonyms: ringworm, circinattina
  • Tinea cruris
    • Dermatophytosis of the medial upper thighs and the inguinal, pubic, perineal, perianal areas
    • Synonyms: eczema marginatum, ringworm of the groin, tinea inguinalis, gym itch
    • Major causative agent: Trichophyton rubrum, others: Trichophyton mentagrophytes, Epidermophyton floccosum
  • Tinea imbrikata
    • Caused by Trichophyton concentricum, only reported from Manado and Papua
  • Tinea pedis (Athlete's foot)
    • Dermatophytosis of the feet
  • Tinea unguium
    • Dermatophytosis of the fingernails or toenails
  • Dermatophytoses laboratory diagnosis
    1. Microscopic examination of KOH 10% preparation of skin scales to detect hyphae
    2. Culture on Sabouraud's agar to identify by mycelium and asexual spores
  • KOH preparation of skin scales from a dermatophytosis patient
    • Epidermal cells lysed
    • Visible long, septate, branching hyphae
    • Hyphae sometimes fragmented into arthrospores
  • In 1980, Trichophyton rubrum was the major causative agent of dermatophytosis, followed by Epidermophyton floccosum, Trichophyton mentagrophytes, and Microsporum canis
  • In 2008, Trichophyton rubrum remained the major causative agent, followed by Trichophyton mentagrophytes, Microsporum canis, and Microsporum gypseum
  • Dermatophytoses treatment
    • Topical agents like miconazole, clotrimazole, tolnaftate, undecylenic acid
    • Griseofulvin
  • Dermatophytoses prevention
    Keep skin dry and cool
  • Pityriasis versicolor (Tinea versicolor)
    • Chronic, mild, usually asymptomatic infection of the stratum corneum
    • Caused by Pityrosporum (Malassezia) furfur
    • Transmitted by direct contact with skin scales
  • Clinical types of Pityriasis versicolor
    • Lesions vary in color (hypo/hyperpigmented) based on patient pigmentation, sun exposure, and severity
    • Lesions on face, neck, shoulders, arms, with slight scaling or itching, usually asymptomatic
  • Pityriasis versicolor laboratory diagnosis
    Direct KOH examination of skin scales shows pathognomonic round, budding yeast cells and short, septate, occasionally branched hyphae fragments
  • Culture is not usually done for Pityriasis versicolor
  • Pityriasis versicolor treatment
    Topical azoles (e.g. miconazole, ketoconazole)
  • Subcutaneous mycoses: Mycetoma
    • Chronic, locally progressive, destructive, suppurative, and granulomatous disease
    • Begins in the subcutaneous tissue, usually of the foot, involving subcutaneous tissue, fascia, and bone
    • Characterized by draining sinuses and presence of granules