L12- Skin fungi Flashcards
1
Q
What are fungi?
A
- Eukaryotic and obtain nutrition from their environment
* May be environmental, commensal or pathogenic
2
Q
What are the main characteristics of yeasts and moulds?
A
- Yeasts are unicellular, reproduce by asexual budding, some produce hyphae and pseudohyphae
- Moulds are multicellular, reproduce using specialised spore structures and produce hyphae
3
Q
How are pseudohyphae and hyphae produced?
A
- Pseudohyphae by bud elongation
* Hyphae by apical extension
4
Q
What are factors predisposing to candidiasis?
A
- Age
- Endocrine disorders
- Defects in T cells
- Cancer
- Immunosuppression
- Drug addiction or therapy
5
Q
What are infections caused by Candida Albicans?
A
- Candidiasis
* Superficial- interdigital, intertrigo (breasts) and onchomyosis and paronchia (nails)
6
Q
How does Candida Albicans cause infections?
A
- Tissue invasion uses phospholipase and protease action, different proteases in different morphological forms and environments
- Toxins such as candidalysin- damages tissue and activates immune response
7
Q
What infections does Malassezia cause?
A
- Pityriasis vesicolor
- Malassezia folliculitis
- Seborrhoeic dermatitis
8
Q
What is the pathogenicity of Malassezia?
A
- Thick cell wall- prevention of phagocytosis and suppression of cytokine production
- Lipases release azelaic acid as a metabolite which reduces ROS killing in neutrophils
9
Q
What are dermatophyte infections?
A
- Commonest cause of human superficial fungal infection
- Called ringworm
- Caused by family of fungi using keratin as a main food source
10
Q
What are examples of dermatophyte infections?
A
- Scalp ringworm
- Scalp infection
- Hands, feet, body- trichophytun rubrum
11
Q
What is mycetoma?
A
- Chronic infection of skin, subcutaneous tissue and bone resulting from traumatic inoculation into dermis
- Abscess forms and drains to surface via sinus
12
Q
What is aspergillosis?
A
- Causes systemic disease following inhalation of spores
* Type of disease determined by host status
