Most fungal spores are _____ (sexual/asexual).
Asexual fungal spores are also known as what?
A gardener has an arm pustule with ascending lymphangitis. You biopsy it and see a fungus. What is it and how do you treat it?
Sporotrichosis ("rose gardener's disease") caused by Sporothrix schenckii; treatment is itraconazole or potassium iodide
A girl has hyperpigmented skin patches. You biopsy the skin and see "spaghetti and meatballs" on KOH prep. Diagnosis?
Tinea versicolor, caused by Malassezia furfur fungus
Name two systemic mycoses that are transmitted by inhalation of asexual spores.
Coccidioidomycosis and histoplasmosis
You see this fungus in the cerebrospinal fluid of an HIV-positive man with meningitis. What is it?
Candida albicans, yeasts with wide capsular halos that exhibit narrow-based budding
What do histoplasmosis, paracoccidioidomycosis, and blastomycosis have in common?
They are all systemic mycoses caused by dimorphic fungi (mold in soil, but yeast in tissue (remember: mold = cold; heat = yeast)
Histoplasmosis is endemic in what area of the United States?
The Mississippi and Ohio River valleys
Histoplasmosis is most commonly transmitted via what substance?
Bird or bat droppings
Blastomycosis is endemic in what areas of the United States?
The states east of the Mississippi River; it is also common in Central America
What is the characteristic microscopic appearance of blastomycosis?
Big, broad-based budding
A 40-year-old male from Central America presents with dyspnea and granulomatous skin nodules. What diagnosis do you expect?
Coccidioidomycosis is endemic in what area of the United States?
The southwestern United States, including California
What microscopic appearance distinguishes coccidioidomycosis from all other dimorphic fungi?
It is a spherule in tissue, not a yeast
What are two colloquial names for disease caused by coccidioidomycosis?
San Joaquin Valley fever and desert valley fever (desert bumps)
Paracoccidioidomycosis is endemic in what area?
The yeast that causes paracoccidioidomycosis has what appearance on microscopy?
The "captains wheel" appearance
What is the treatment of choice for local infection with dimorphic fungi?
Fluconazole or ketoconazole
What is the treatment of choice for systemic infection with dimorphic fungi?
Systemic mycoses can mimic which other infectious disease with granuloma formation?
Histoplasmosis has what appearance under microscopy?
Macrophages filled with yeast (remember: Histo Hides in macrophages)
All systemic mycoses can cause what type of illness?
Pneumonia that can disseminate
In addition to pneumonia, what other illnesses can coccidioidomycosis cause?
Meningitis with dissemination to skin and bone
Describe the sizes of the four dimorphic fungi in relation to the size of a red blood cell.
Histoplasmosis: smaller; blastomycosis: same; coccidioidomycosis and paracoccidioidomycosis: larger
Tinea versicolor is caused by what organism?
An athlete presents with hypopigmented macules on her upper back after a summer of exercising. What is your diagnosis and what is the treatment?
Tinea versicolor; treat with topical miconazole and selenium sulfide
What are the characteristic skin lesions of tinea pedis, cruris, corporis, and capitis?
Pruritic lesions with central clearing that resembles a ring (the infection is colloquially known as ringworm)
Tinea pedis, tinea cruris, tinea corporis, and tinea capitis are caused by what organisms?
Dermatophytes (ie, Microsporum, Trichophyton, Epidermophyton)
What animals are commonly reservoirs for Microsporum?
What is the typical microscopic appearance of the agent causing tinea versicolor on KOH prep?
"Spaghetti and meatballs" (Malassezia furfur)