Superficial, Cutaneous and Subcutaneous fungal infections

Question 1

What are the clinical classifications of human mycoses?

Answer 1

Mycoses are classified as superficial, cutaneous, subcutaneous, or systemic (deep) infections depending on the type and degree of tissue involvement and the host response to the pathogen.

Question 2

What are the three genera of fungi that make up the dermatophytes?

Answer 2

Three common species:
Trichophyton
Microsporum
Epidermophyton

Question 3

Descibe the typical lesion of tinea

Answer 3

Annular lesion, which spreads centrifugally, may be sharply defined, displays peripheral activity and tends to heal in the centre

Question 4

Where does tinea occur, and how does the lesion change depending on body site?

Answer 4

In and around hair: can cause hair loss, and scales but still annular
Horny layer of skin: usually the well defined circular lesion
Warm, moist skin folds: in is lichenified with a small amount of scale
Just under nails: nail becomes thick, crumbly and discoloured

Question 5

What does a nail infected with a dermatophyte look like?

Answer 5

Thick, crumbly and discoloured, usually around the distal and lateral nail borders

Question 6

What is the appearance of tinea capitis?

Answer 6

Gradual appearance of round patches of dry scale, alopecia, or both

Question 7

What is the appearance of tinea kerion?

Answer 7

“Kerion celsi” - deepest dermatophyte infection of the scalp, and is accompanied by marked cervical lymphadenopathy and fever, as well as severe local inflammation, with tender erythematous exudative swelling and hair loss

Question 8

What is the appearance of cutaneous candidiasis?

Answer 8

Scaling and maceration of the skin
Red, itchy rash
Potentially blisters/pustules

Question 9

What is the appearance of mucous membrane candidiasis?

Answer 9

Classical discharge: milky white, thick discharge with curd-like chunks, inflamed and swollen mucosa. Will also be painful and itchy

Question 10

What are the features constituting a sporotrichoid infection?

Answer 10

Small papule on periphery of trauma site
Gradual development of non-healing ulcer
Pus filled red swellings moving up the limb

Question 11

Name three organisms that produce sporotrichoid lesions

Answer 11

• Sporothrix Schenckii
• Bacteria including Nocardia
• Mycobacterium marinum

Question 12

What does pityriasis look like microscopically?

Answer 12

Fungal elements, short sausage shaped elements and groups of yeast-like cells in “spaghetti and meatballs” arrangement