Fungal Infections

Question 1

Tinea Versicolor

Answer 1

Malassezia furfur- yeast part of normal flora converts to mold in disease, requires lipids so predominantly found in areas rich in sebaceous glands, in individuals 15-24yrs old, and in tropical climates.

Symptoms: Hypo or hyperpigmentation

Treatment -azole creams

Question 2

Seborrheic dermatitis, sclay (cradle cap)

Answer 2

Infectious agent: Malassezia furfur

Diagnosis: Skin scraping “spaghetti and meatballs”

Treatment: Topiclal therapy: selenium sulfide or ketoconazole shampoo. Reoccurence common

Question 3

Dermatophytoses, “ringworm” “tinea” jock itch, athlete’s foot

Answer 3

Causative agents: Trichophyton, Microsporum, or Epidermophyton (very common men>women)

Pathogenesis: Monomorphic molds enter through skin breaks, secrete proteases and keratinases. Fungal antigens cause inflammation (Kerion). Grow best at 25C, can’t live at 37C so rarely see further invasion

Diagnosis: KOH test, grow on Sabouraud’s agar

Treatment: Topical griseofulvin, terbinafine or itraconazole. 1 month. Oral for nail, and hair (monitor hepatotoxicity) Often reoccur.

Question 4

Tinea pedis

Answer 4

Causative agent: most common is Trichophyton rubrum.

Symptoms: serpentine lesions with central clearing. Anthropophilic (human to human)- moist areas of skin, transfer at swimming pools.

Question 5

Tinea capitis

Answer 5

Causative agent: Trichophyton tonsurans infections are most common cause in US

Question 6

Microsporum - hair (ectothrix) and skin

Answer 6

Causative agents: Microsporum canis - zoophilic (cats, dogs) Microsporum fulvum - geophilic (soil)

Diagnosis: Wood’s light blue green.

Question 7

Epidermophyton floccosum

Answer 7

can cause tinea cruris and tinea pedis. Less common than other two species. Lacks microconidia. Anthropophilic spread.

Question 8

Rose gardener’s disease

Answer 8

Causative agent: Sporothrix schenckii due to puncture of the hand from infected plant.

Pathogenesis: Fungi spread from initial lesion along lympahtics forming nodular lesions. Extracutaneous sporotrichosis in immunocompimised patients.

Diagnosis: Need lymph node culturing.

TreatmentL Oral itraconazole for 3-6 months.

Question 9

Candida albicans

Answer 9

Commensal, most infections are endogenous

Superficial infections- Diaper dermatitis, at corners of the mouth (angular cheilitis), in toenail or edge of nails (paronychia), oropharyngeal (thrush). Also responsible for vaginal and systemic infections.

Diagnosis: Based on clinical appearance but can do skin scraping

Pathogenesis: Seeds in areas with less normal flora (antibiotic treatment) Chronic mucocutaneous candidiasis may suggest individual has T cell dysfunction. May also be a sign of diabetes.

Treatment: Keep skin dry, Clotrimazole or other -azole cream.