Infections & Infestations (Wanat) Flashcards
- contagious skin infection common in children
- often caused by staph aureus or group A strep
- results in thin walled vesicles that rupture forming honey colored crust
- treat with topical mupirocin
impetigo
- deep form of impetigo
- crusted sores and deeper erosions/ulcerations
ecthyma
- superficial lymphatic infection due to Group A strep
- Painful, sharply marginated red plaque
- patients (children, elderly, chronic lymphedema) often febrile and systemically ill
- treat with penicillin
erysipelas
*note the hot, red, painful lesion
very similar clinical presentation to erysipelas, except whereas erysipelas involves the upper dermis and superficial lymphatics, this infection involves the deeper dermis and subcutaneous fat
cellulitis
*treatment regimens should include coverage both for group A strep and staph aureus.
inflammation of a hair follicle, commonly caused by S. aureus is known as ______
folliculitis
What is the best way to treat an abscess?
A. Warm compress
B. Incision and drainage
C. No treatment necessary
D. Acyclovir
B
This is the treatment of choice for ca-MRSA and antibiotics are typically not needed.
In the event that antibiotics are needed to clear a MRSA abscess, which class of antibiotics is the 1st line choice?
tetracyclines or clindamycin (a lincosamide)
A `16-year-old wrestler presents to the clinic with annular, erythmematous pruritic plaques on his inner thighs. What is the likely diagnosis?
A. Tinea corporis
B. Tinea faciei
C. Tinea pedis
D. Tinea cruris
E. Tinea capitis
D
Otherwise knowns as “jock itch”
boggy erythematous nodules common in young children, that present with patchy hair loss, crust, scale and pustules; often accompanied by lymphadenopathy
tinea capitis
*must treat systemically with griseofulvin, terbinafine, or triazole
this non-inflammatory, seborrheic dermatitis-like infection is characterized on a KOH prep by branching septate hyphae:
tinea capitis
caused by our old friend, Malassezia furfur, this skin infection thrives in hot and humid temperatures, leading to asymptomatic hyper- or hypo-pigmented slightly scaly macules on the upper trunk, neck and proximal arms
Pityriasis versicolor (AKA tinea versicolor, AKA “sun fungus”)
*treated topically with zinc pyrithione, selenium sulfide, or imidazoles
**spaghetti and meatballs on KOH
infection within the nail plate that requires systemic treatment with terbinafine, itraconazole or fluconazole
onychomycosis
bright red patches with satellite pustules, commonly found in infants, diabetics, or people who are obese or using antibiotics
(muco)cutaneous candidiasis
what will be seen on a KOH prep of candida?
budding yeast and pseudohyphae (aseptate, non-branching)
pathophysiology of this type of infection includes an acute phase marked by tissue destruction with immune clearance, followed by latency in the dorsal root ganglion and eventual reactivation
herpes virus infections
a blister caused by HSV that is scraped and plated on a Tzanck prep will show what feature under microscopy?
multinucleated giant cells with enlarged nuclei and nuclear moulding (conformity of adjacent cells to one another):
eruption of this infection starts on the head, neck, and trunk and spreads centrifugally outward with “dew drop on a rose petal” vesicles
varicella (chickn pox)
How are herpetic infections treated?
A. Acyclovir
B. Penicillin
C. Fluconazole
D. Permethrin
E. Mupirocin
A
*Acyclovir is a thymidine kinase inhibitor
this infection is caused by a DNA poxvirus and affects the skin and mucous membranes as translucent papules with a central umbilication:
Molluscum contagiosum
this is a contagious infestation of the stratum corneum, and often involves the hands, feet and genitalia; results in dermal inflammation and eosinophilia ⇒ SUPER itchy
scabies
*mite burrows are most common in the interdigital spaces
Which of the following statements about scabetic infestations is FALSE?
A. Burrows are the only location where a mite is found in scabies infestation
B. Pruritic genital nodules are virtually diagnostic for scabies
C. It takes weeks for itching to go away following treatment, because mites persist in pruritic nodules
D. The best treatment for a scabies infection is permethrin.
E. Scabies are highly infectious and are transmitted via close contact with an infected individual.
C. The pruritic nodules of scabies represent a hypersensitivity reaction to the scabetic infestation, which is why itching persists. The mites themselves don’t live there, and are only found in (linear) burrows of the skin:
