Published on March 9, 2014
Superficial Mycoses Dr. Pendru Raghunath Reddy
SUPERFICIAL MYCOSES The superficial mycoses are usually confined to the outermost layer of skin, hair, mucosa and do not invade living tissues
Superficial mycoses • • • • Do not elicit immune response No discomfort Cosmetic problems Limited to stratum corneum
Superficial Mycoses 1. Pityriasis versicolor 2. Tinea nigra 3. Black piedra 4. White piedra
Pityriasis Versicolor Caused by Malassezia furfur (Pityrosporum orbiculare) lipophilic yeast Found as a normal flora on the skin Rich in sebaceous glands Grows on media supplemented with fatty acids Exist in budding yeast,occasionally hyphal Diseases : Pityriasis versicolor Pityriasis folliculitis Seborrhoeic dermatitis; Dandruff Systemic infection
Major clinical manifestations: – Hyper- or hypopigmented of the skin – Lesions are well-demarcated (white, pink or brownish) – Fawn-colored macules are the most common presentation Trunk and upper arms Rarely on neck and face
Pityriasis folliculitis follicular papules and pustules back, chest and upper arms sometimes the neck, seldom the face Itchy and often appear after sun exposure
Seborrhoeic dermatitis Changes in quantity and composition of sebum increase in wax esters shift from triglycerides to shorter fatty acid chains Increase in alkalinity of skin External local factors such as occlusion
Clinical manifestations: Erythema and scaling in areas with a rich supply of sebaceous glands scalp, face, eyebrows, ears and upper trunk Lesions are covered with greasy scales Itching is common in the scalp
Laboratory diagnosis Specimen: Skin scrapings Methods: 1. KOH preparation 2. Culture KOH preparation Both budding yeast cells and hyphae can be demonstrated Shows characteristic ‘spaghetti and meatballs’ appearance
•Short fragments of hyphae •clusters of yeast • Spaghetti and meatballs appearance
Culture M. furfur requires fatty acids for growth, hence is cultured on SDA with a layer of olive oil Colonies of M. furfur on Dixon's agar. A specialized isolation medium containing glycerol-mono-oleate
Management and Treatment: 1. Topical agent: imidazole (Ketoconazole shampoo) 2. Oral treatment : ketoconazole, itraconazole 3. Alternative: zinc pyrithione shampoo • selenium sulfide lotion • propylene glycol 50% in water twice daily
TINEA NIGRA • Tinea nigra is an infection of keratinised layer of skin caused by Exophiala werneckii or Cladosporium werneckii • C. werneckii is a dimorphic fungus that produces melanin
A well-demarcated brown-black macular lesions which usually occur on the palmar aspects of hands and occasionally the plantar and other surfaces of the skin Lesions are non-inflammatory and non-scaling •palmar •brown •no scaling •no inflammation
Laboratory diagnosis KOH preparation Microscopy of the KOH preparation of skin scrapings collected from the affected part Typical darkly pigmented yeast-like cells and hyperfragmented hyphae are demonstrated
Culture Initially colonies are mucoid, yeast-like and shiny black (young yeast) Abundant aerial mycelia and become velvety, dark olivaceous in colour. (mature mould)
Management & Treatment Sulfur soap, SSA, azoles Topical treatment Whitfield's ointment (benzoic acid compound) Imidazole agent twice a day for 3-4 weeks 23
Black Piedra • Black piedra is a superficial infection of the hair caused by Piedraia hortae, a dematiaceous fungus Clinical Manifestations Does not penetrate the hair follicle presence of hard nodules found along the infected hair shaft Nodules: hard, fusiform, firmly attached to hair shaft
Laboratory diagnosis Demonstration of nodules containing asci with spindle shaped ascospores in 10% KOH mount of the hair
Management and Treament Shave or cut the hairs short Terbinafine Dose: 250 mg a day for 6 weeks
White Piedra • Infection of the hair caused by yeast-like organism Trichosporon beigelli • Commonly found in South America, Central and Eastern Europe and Japan • The hair of scalp, moustache, and beard are commonly affected • The development of a soft, pasty, cream-colored growth along infected hair shaft characterizes the condition • The initial growth occurs beneath the epidermis of hair • The infected hair shaft consists of mycelium that rapidly fragments to arthroconidia
In this picture we see hair with white piedra (Trichosporon beigelii). Note that, when this module is compared with that seen in black piedra, it is not as discrete and lacks the dark coloration. Additionally, this fungus does not produce ascospores. When cultured on Sabouraud’s agar and incubated for 2-4 weeks at room temperature, this fungus produces a rough, membranous, white to light tan colony. Microscopically, the organism produces no characteristic spores.
Laboratory diagnosis 1. Direct Microscopy Fragmented hyphae that develop into arthroconidia or produce blastoconidia in 10% KOH mount of hair
2. Culture Grown on SDA with cycloheximide White or yellowish to deep cream colored Smooth, wrinkled, velvety, dull colonies with a mycelial fringe This is a 4-5 weeks old culture of Trichosporon beigelii grown on SDA agar at room temperature
Management and Treatment Shave the hairs Topical: imidazole agent
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The superficial (cutaneous) mycoses are usually confined to the outer layers of skin, hair, and nails, and do not invade living tissues. The fungi are ...
Superficial and Cutaneous Mycoses (1) - Download as Powerpoint Presentation (.ppt), PDF File (.pdf), Text File (.txt) or view presentation slides online.
Superficial mycoses ... Cutaneous mycoses. Cutaneous mycoses extend deeper into the epidermis, and also include invasive hair and nail diseases.
Superficial Mycoses . These are superficial cosmetic fungal infections of the skin or hair shaft. No living tissue is invaded and there is no cellular ...
Diseases tinea versicolor . a superficial infection of keratinized cells; leads to ...
Superficial and Cutaneous Mycoses . Superficial Mycoses include. the following fungal infections and their etiological agent: black piedra (Piedraia hortae),