Microbiology Flashcards
impetigo
epi: children
- bullous in neonates
- contracted from direct contact or fomites
patho:
- non-bullous: staph aureus, compromises skin barrier –> infection
- bullous: s. aureus phage II, type 71, secreted toxins disrupt demsogleins, occurs on intact and compromised skin
clinical:
- non-bullous: honey colored crust, vesicles, pustules, non healing wound
- bullous: flaccid bullae, malaise, fever, diarrhea, rapid resolution
diagnosis: clinical pres, superficial culture
treatment: cover sites, topical antibio (mupirocin) for localized, oral antibio for generalized
Ecthyma
epi: trauma
patho: strep pyogenes or staph aureus
clin pres: pustules and vesicles –> ulcers with crust –> scarring
diag: wound culture
treat: oral antibio
abscess, furuncle, carbuncle
abscess=collection of pus w/ surrounding fibrous rxn
furuncle=abscess w/ hair follicle
carbuncle=collection of furuncles
epi: adol and adults
- risks: diab mell, elderly, immunosupp, obesity, poor hygiene
patho: s. aureus, anaerobic bact
clin: tender, red nodule that becomes fluctuant, systemic symptoms absent
diag: clin. appear, culture of purulent exudate
treat: warm compress for non-fluctuant, incision and drain for fluctuant (except breast)
- oral antibio if: perinasal abscess, large and recurrent lesion, surrounding cellulitis, failure to respond to local measures
erysipelas
epi: elderly
patho: strep pyogenes
clin: erythematous plaque w/ sharp demarcated border
- face and extremities
- fever, chills, and malaise may herald onset
- lymphatic destruction in recurrent infections
diag: clin present
treat: oral antibio
erythrasma
epi: adult
patho: corynebacterium minutissimum
clin: well defined, erythematous patches w/ fine scale
- axilla, inguinal folds, gluteal cleft, moist areas
- usually asymptomatic
diagnosis: wood’s lamp = coral red fluorescence
treat: topical antibio or antifungal (antiinflam)
tinea corporis, capitis, pedis, cruris
epi:
- capitis (head): children
- corporis (body), pedis (feet), cruris (groin): adults
- unguium (nails) (onychomycosis): adults
patho:
- dermatophytes: trichophyton, epidermophyton, microsporum
- anthropophilic, zoophilic, geophilic
clin:
- capitis: white, scaling patches w/ hair loss
- corporis: erythematous, scaling plaques w/ annular configuration
- cruris: erythematous, macerated patched of inguinal folds (scrotum spared)
- pedis: variable plantar erythema and scale, vesicles, pustules, interdigital maceration
onychomoyosis: yellow, subungal hyperkeratosis or superficial white scale
diag: KOH exam = branching hyphae (septate)
culture for tinea capitis and onychomycosis
treat: topical antifungals (clotrimazole, terbinafine)
pityriasis (tinea) versicolor
epi: after pub, young adults
patho: malassezia furfur (yeast), direct contact
clin: asym, macules and patches w/ fine, white, superficial scale, pink in winter, hypopig in summer
diag: KOH = short hyphae and spore clusters “getti and balls”
treat: topic or oral antifungals, selenium sulfide
cutaneous candidiasis
epi: summer/high humidity, obesity, diaper dermatitis
patho: candida yeast
clin:
- intertrigo: erythematous patches w/ satellite papules and pustules, maceration, foul odor, may involve scrotum
- diaper dermatitis: red papules and plaques w/ erosions
diag: KOH = pseudohyphae (nonseptate chains of yeast)
treatment: topical antifungal (clotrimazole, nystatin), zinc oxide paste
seborrheic dermatitis
epi: infants
anti seborrheic shampoos
zinc
selenium sulfide
ketoconazole
tar
herpes simplex (HSV) infection
epi:
- HSV 1=oral
- HSV2=genital
- high I of subclinical infection
patho: direct (fomites)
clin: tingling, scalloped border, painful uniform vesicles on red base that become eroded and crusted
- lymphadenopathy may occur w/ 1* inf.
diag: clin present, Tzanck prep reveals multinucleated cells, PCR
treat: oral antiviral (ayclovir, famcilovir, valacyclovir) w/in 48 hrs of onset
erythema multiform (EM)
recurrent, self limited eruption of skin/oral mucosa, *targetoid macules
may occur concurrently w/ subclin HSV inf. –> rxn to underlying inf so HSV not present in kin lesions
varicella zoster (VZV) *shingles
epi: varicella, elderly & immunosuppressed, risk of posttherpetic neuralgia for them
patho: retro to DRG
clin: tingling, pain, vesicles, maybe lymphadenopathy
diag: clin, Tzanck prep shows mutlinuc. giant cells
treatment: oral antivirals, VZV vaccine
warts
patho: direct contact, HPV infects basal keratinocytes, condyloma acuminata=genital mucosa warts
clin: skin colored papillose w/ rough surface
may have/be: black dots, flat, thick scale
diag: clin, applying vinegar/acetowhite helps detection
treatment: salicylic acid, cryotherapy, immunotherapy, electrodessication and curettage, laser, HPV vaccine
HPV subtypes that inc. risk of cervical cancer
16, 18, 33, 35
