Superficial and cutaneous mycoses

67 %
33 %
Information about Superficial and cutaneous mycoses
Education

Published on March 9, 2014

Author: raghunathp

Source: slideshare.net

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

Pityriasis folliculitis

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

14

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

Culture

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

Add a comment

Related presentations

Related pages

Mycology Online | The Cutaneous Mycoses

The Cutaneous Mycoses. These are superficial fungal infections of the skin, hair or nails. No living tissue is invaded, however a variety of pathological ...
Read more

Spectrum of Mycoses - Medical Microbiology - NCBI Bookshelf

Classification Based on Site. Mycoses are classified as superficial, cutaneous, subcutaneous, or systemic (deep) infections depending on the type and ...
Read more

Superficial (cutaneous) mycoses - Microbiology Book

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 ...
Read more

Superficial and Cutaneous Mycoses (1) - scribd.com

Superficial and Cutaneous Mycoses (1) - Download as Powerpoint Presentation (.ppt), PDF File (.pdf), Text File (.txt) or view presentation slides online.
Read more

Mycosis - Wikipedia, the free encyclopedia

Superficial mycoses ... Cutaneous mycoses. Cutaneous mycoses extend deeper into the epidermis, and also include invasive hair and nail diseases.
Read more

Mycology Online | Superficial Mycoses

Superficial Mycoses . These are superficial cosmetic fungal infections of the skin or hair shaft. No living tissue is invaded and there is no cellular ...
Read more

Cutaneous and Subcutaneous Mycoses - Medbullets.com

Diseases tinea versicolor . a superficial infection of keratinized cells; leads to ...
Read more

Spectrum of Mycoses - LU

Superficial and Cutaneous Mycoses . Superficial Mycoses include. the following fungal infections and their etiological agent: black piedra (Piedraia hortae),
Read more