Cutaneous Fungal Infections and Parasitic Infestations

Comprehensive vocabulary flashcards covering cutaneous fungal infections (yeasts, molds, dermatophytes), their pathogenesis, diagnosis, and various parasitic infestations mentioned in the lecture.

Fungus

A plant-like organism that does not produce chlorophyll; examples include mushrooms, yeasts, and molds.

Yeasts

Microscopic, unicellular, oval-shaped organisms that reproduce by budding rather than sporing.

Molds

Multicellular organisms that grow as hyphae or mycelium, appear fuzzy in various colours, and produce spores.

Primary infection

A disease state arising in a healthy host.

Opportunistic infection

A disease state arising in a host with a compromised immune system.

Dermatophytes

Fungi that invade and feed specifically on keratinized tissue, including skin, hair, and nails.

Trichophyton

One of the three main genera of dermatophytes that causes infections in the skin, hair, and nails.

Epidermophyton

A genus of dermatophytes that causes infections specifically in the skin.

Microsporum

A genus of dermatophytes that causes infections in the skin and hair.

Tinea capitis

A dermatophytosis of the scalp that primarily affects children aged 3 to 14 years and may present as inflammatory (kerion, favus) or non-inflammatory.

T. rubrum mannans

Substances produced by T. rubrum that can inhibit lymphocyte action.

KOH Direct Microscopic Examination

A diagnostic method using $10-40\%$ Potassium Hydroxide to visualize refractile, branching, septate hyphal filaments from skin scrapings.

Tinea unguium

A fungal infection of the nails, also categorized as a systemic antifungal indication.

Tinea incognito

A fungal skin infection that has been modified clinicaly due to the inappropriate use of topical steroids.

Candida albicans

The primary yeast species responsible for human cutaneous candidiasis infections.

Intertrigo

A fungal infection occurring in skin folds characterized by erythema and satellite lesions (macules, papules, or pustules).

Malassezia

Lipophilic yeasts that are part of the normal skin flora but can become pathogenic under favorable conditions.

Pityriasis versicolor

A Malassezia-induced infection resulting in hypopigmented or brown, well-demarcated macules with a "spaghetti and meatballs" appearance on KOH microscopy.

Cutaneous larva migrans

An infestation caused by the percutaneous penetration and migration of hookworm larvae, presenting as highly pruritic, serpiginous, or linear papules.

Cutaneous Myiasis

An infestation of the skin by the developing larvae of fly species such as Dermatobia hominis (human botfly) or Cordylobia anthropophaga (tumbu fly).

Scabies

An intensely pruritic infestation caused by Sarcoptes scabiei hominis, characterized by pathognomonic burrows in webbed spaces or flexor surfaces.

Lymphatic filariasis

A mosquito-transmitted infection caused by Wuchereria bancrofti, Brugia malayi, or B. timori that lodge in the lymphatic system.

Onchocerciasis

A chronic infection caused by Onchocercus volvulus, transmitted by the female black fly near fast-moving water, commonly presenting with pruritic papules and onchonodules.

Leishmaniasis

A disease caused by the intracellular protozoan Leishmania, transmitted via the bite of a female sandfly, which can present in localized, diffuse, or mucocutaneous forms.

Post-kala-azar dermal leishmaniasis

Cutaneous lesions ranging from hypopigmented macules to nodules that appear months after recovery from visceral leishmaniasis.