Mycology Study Guide

Fungal infection of the outermost layer of th skin and hair

* Type of Otitis external
* Most commonly caused by Asperqillus, Perrillium, Mucor, and Rhizopus spp, less commonly by dermatophytes
* Microscopic observ. of asexual spores in KOH prep

*Fungal infection of scalp, hair and possibly eyebrows, eyelashes, and pubic hair, and characterized by hard, gritty, dark brown or black nodules of barious sizeand shape on hair shafts.
* Endemic in tropical areas of Africa, Asia, and S. America
*Caused by the mould Piedraia hortae
*Microscopic observ. of dark, thick-walled, septate hyphae w-numerous chamydoconidia

Fungal inf. of mustache, beard, pubic and axilla hair, and characterized by soft, pigmented (white, tan, yellow, or green) nodules of various sizes on hair shafts
* Endemic in S. America, Far East, and the Pacific
*Caused by Trichosporon Spp., primarily T. Beigelii.
* Microscopic: hayaline hyphae, arthroconidia, and blastoconidia

*Ringworm infecton usually of chest or back
* Characterized by irregular scaly patches that can be pigmented (brown, yellow, or red) and seen with a Wood's lamp that emits UV light.
*Primary cause are moulds in the Malassezia furfur complex.
*Microscopic: obal budding cells w-hyphae that gives a "spaghetti and meatball" appearance

* Ringworm infect. most oftern of the palms of the hands.
* Charac. by flat, sharply, marginated, brown-black, nonscaly macular lesions.
*caused by the mould Hortae werneckii
*Microscopic: Blastoconidia or budding cells that develop laterally from dark hyphae

*Depends on inf. location: includes skin scrappings, hair clippings, ear canal debris, and exudatee.
*Skin cleaned w-alcohol, then scraped, or colleded w-scotch tape.

*Skin and hair: KOH prep or calcoflour white stain.
*Ear canal: Gram Stain
*Scotch tape specimens placed sticky side down onto a drop of lactophenol cotton blue

*Rarely cultured, but Sabouraud dextrose agar used if cultured

Fungal inf. of th living layers of the skin, hair shafts, and nails (commonly called tinea or ringworm inf.) are caused by a group of moulds called dermatophytes

Epidernophyton spp., Microsporum spp., and Trichophyton spp.

Beard and mustache

Scalp, eyebrows, and eyelashes

Face, trunk, arms, and legs

Scalp