Dermatophytoses and Dermatomycoses

Question 1

Dermatophytoses organisms

Answer 1

• Microsporum
• Trichophyton

Question 2

Dermatomycoses organisms

Answer 2

Malassezia

Question 3

Subcutaneous mycosis organisms

Answer 3

Sporothrix

Question 4

Dermatophyte characteristics and classes

Answer 4

• molds capable of parasitizing only keratinized epidermal structures (ex: hair, skin, nails)
• anthropophilic= humans
• zoophilic= animals and humans
• geophillic= soil associated

Question 5

Microsporum important species & characteristics

Answer 5

• -M. canis*= MOST COMMON dematophyte of domestic animals
• large macroconidia, rough, thick-walled and multiseptate
• microconidia may occur singly along hyphae

Question 6

Microsporum disease patterns

Answer 6

ringworm

Question 7

Trichophyton important species & characteristics

Answer 7

• T. mentagrophytes: cats, dog, rodents, humans
• macroconidia are smooth, thin-walled and cylindrical
• occur in small numbers
• sometimes many microconidia

Question 8

Trichophyton disease patterns and diagnosis

Answer 8

• ringworm
• make skin scrape w/cotton blue stain
• ectothrix distribution of spores
• “derm-duet” test (yellow to red=dermatophyte)

Question 9

Control and treatment of dermatophytoses

Answer 9

• sanitation
• vaccine available for cattle
• topical antifungals
• ketaconazole

Question 10

Malassezia characteristics

Answer 10

• yeast
• peanut shaped
• cutaneous normal microflora
• lipophillic, found near sebaceous gland secretions

Question 11

Malassezia disease patterns

Answer 11

Dogs: otitis externa, dermatitis

Cats: otitis externa, chin acne

Question 12

Malassezia treatment

Answer 12

• correct underlying conditions
• topical miconazole
• systemic itraconazole/ketaconazole

Question 13

Subcutaneous mycoses characteristics and important species

Answer 13

• involve deeper layers of skin, associated with trauma
• rarely disseminate
• Sporothrix (sporotrichosis)

Question 14

Sporothrix characteristics

Answer 14

• thermally dimorphic (mold at cooler temps, yeast at higher temps)
• zoonotic potential

Question 15

Sporothrix disease patterns?

Answer 15

• Cat: outdoor cats with puncture wounds (near tail)
• Dog: cutaneous, lymphocutaneous, and disseminated lesions
• Horse: hard cutaneous nodules on legs

Question 16

Sporothrix treatment

Answer 16

itraconazole, amphotericin B (more toxic but effective)