Dermatology 3 Flashcards

1
Q

Which bacteria account for a majority of the skin infections?

A

staph aureus and A beta hemoltic strep, S. aureus invades skin and causes impetigo, folliculitis, cellulitis and furuncles; strep invade traumatic lesions and cause impetigo, erysipelas, cellulitis and lymphangitis

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2
Q

Impetigo

A

common, contagious, superficial skin infection that is produced by strep, staph, or combo; bullous and nonbullous impetigo, both begin as vesicles w/ very thin, fragile roof consisting only of stratum corneum

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3
Q

What may follow impetigo

A

poststrep gn

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4
Q

Bullous impetigo

A

epidermolytic toxin, causes intraepidermal cleavage below or within the stratum granulosum, common in infants/children, 1+ vesicles enlarge-> bulla, clear and cloudy, thin flat, honey colored crust, disclosed+ bright red, inflamed, moist oozing base, tinea like scaling

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5
Q

Nonbullous impetigo

A

small vesicle or papule that ruptures to expose a red moist base, sequence of events- bac-> carriage on skin-> infection post trauma; honey-yellow to brown, firmly adherent crust accumulates as the lesion extends,

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6
Q

Nonbullous impetigo lesions

A

satellite lesions appear beyond periphery, usually appear on nose, mouth, and limbs, untreated lesions may last weeks, heal without scarring

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7
Q

Treatment of impetigo

A

prevent w/ mupirocin or triple abx TID, pt w/ recurrent impeigo should test for S. aureus, nares most common site, treat carriers, isolate until tx, oral abx- dicloxacillin, cephalosporin, mupirocin ointment

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8
Q

Cellulitis

A

an infection of dermis and subcutaneous tissue, no clear distinction between infected and uninfected skin, H. influenzae is most common etiologic agent in children

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9
Q

Erysipelas

A

acute inflammatory cellulitis w/ lymphatic involvement, infected area is raised, a distinct demarcation in involved and normal skin, lower legs, face and ears are most commonly involved, also called st. anthony’s fire due to its bright red intensity

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10
Q

Treatment of cellulitis

A

dicloxacillin or a cephalosporin, vancomycin in pts allergic to penicillin, cefotaxime and ceftriaxone are effective, rifampin prophylaxis for fam

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11
Q

H. Influenzae cellulitis treatment

A

must be prompt before gas formation/purulent collections, requires surgical drainage

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12
Q

Folliculitis

A

inflammation of follicle, infection, chemical, or physical injury, superficial folliculitis is confined to upper part of hair follicle, manifests as painless, tender pusutles that heal w/out scarring; deeper lesions scar

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13
Q

Types of folliculitis that are painless or tender pustules

A

Staph, pseudofolliculitis barbae, candidiasis, acne, keratosis pilaris

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14
Q

Types of folliculitis that are painful

A

furuncle, carbuncle, cysic acne, pseudomonas folliculitis

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15
Q

Pseudofolliculitis barbae

A

foreign body to hair, cheeks and neck in individuals who have tight curls that become ingrown, blacks, tender, red papule or pusule occurs at point of entry and remains until hair is removed

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16
Q

Treatment of pseudofolliculitis barbae

A

permanent hair removal with laser assisted hair removal

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17
Q

Sycosis barbae

A

sycosis implies follicular inflammation of the entire depth of follicle, caused by S. aureus or dermatophyte fungi, men who begin shaving, fungal deep infection, bacterial-discrete papules, similar to p. barbae but more inflammation

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18
Q

Sycosis barbae treatment

A

localized infection can be treated with mupirocin, extensive treated w/ abx

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19
Q

Furuncle

A

walled-off collection of pus, painful, firm or fluctuant mass, prone in areas of friction, s. aureus, begins as deep, tender, firm, red papule that enlarges rapidly, may have fever, malaise, chills

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20
Q

Treatment of furuncle/carbuncle

A

warm compresses, localization and pointing of abscess,, incision, drainagge, packing, don’t drain until skin is thinned and mass is soft, culture and gram stain, abx, r/o diabetes in recurrent infection

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21
Q

Pseudomonas folliculitis

A

infects warm, moist areas, whirlpool, hot tub use, few to >50 pruritic, round urticarial plaques w/ central papule or pustule on all surfaces, self-limiting, 5% acitec acid wet compresses, silvadene cream, cipro 500mg-750 mg BID

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22
Q

Verruca vulgaris

A

Benign epidermal growth caused by HPVs, more than 100 different types discovered each year, transmitted by touch, sites of trauma, swimming pools, warts obscure normal skin lines, begin smooth, flesh colored-> dome shaped, gray

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23
Q

Verruca vulgaris treatment

A

requires several tx sessions, topical salicylic acid prep, liquid N, light electrocautery, blunt dissection for resistant/ very large lesions, cryotherapy

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24
Q

Cryotherapy

A

spray liquid N so 1-2 mm zone of frozen tissue is created and maintained for 5 secs, allow to thaw and repeat once or twice to increase cure rates, small blisters and sometimes bleeding appears, may repeat 2-4 weeks

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25
Verruca plana (flat warts)
Pink, light brown or light yellow, flat topped papule .1-.5 cm, common on forehead, mouth, back of hands, shaved areas, resistant to tx
26
Treatment of verruca plana
aldara cream, liquid N or light electrocautery, 5-fluorouracil applied 1-2x for 3-5 weeks
27
Plantar warts
on soles, pt refer to many warts as plantar, occur at point of max pressure, head of metatarsal bones or heels
28
Corns can be distinguished from plantar warts by
paring the callus, corns have hard, painful, well demarcated, translucent central core, warts have central black dots
29
Black heel
horizontally arranged clusters of blue-black dots
30
Treatment of plantar warts
don't treat unless painless, debride hyperkeratotic tissue, salicylic acid liquid, blunt dissection, aldara cream, cantharidin mixture w/podophyllin and salicylic acid, lasar treatment, cryosurgery
31
Molluscum contagiosum
poxvirus infcn, discrete 2-5 mm slightly umbilicated, flesh colored dome shaped papules, spreads by autoinoculation, touching or scratching, face, trunk, axillae, and extremities common sites, most are self limiting, heal 6-9 months
32
molluscum contagiosum treatment
Curettage- destroy top part of skin, cryosurgery, cantharidin, extract from blister beetle is effective, not > 20 lesions in one visit, diff in children, aldara cream, retin A, salicylic cream TCA, laser tx
33
Herpes Simplex
Caused by HSV1/2, HSV1- oral infections, HSV2- genital, both produce identical pattern, genital recurrence are 6x more frequent, primary infection-virus established in nerve ganglion, secondary- recurrent at same site
34
Primary infection of HSV
asymptomatic and can be detected by elevated igG ab titer, spread via resp droplet, direct contact or virus containing fluid, saliva or cervical secretions, uniform vesicles uniform size- 2-4 weeks, virus replicates at site
35
Recurrent infection HSV
local trauma, systemic change, prodromal sx- itching and burning 2-24 hrs (can prevent if treated), 12 hrs- vesicles and papules may appear
36
Treatment of HSV
acyclovir cream, denavir cream, abreva, oral antiviral plus topical steroid, oral antivirals- acyclovir, valtrex, famvir
37
Cutaneous herpes simplex
herpetic whitlow- fingers, peds or females w/genital; herpes gladiatorum- waist, skin-skin contact, wrestlers; herpes on buttocks- women, herpes simplex of the trunk
38
Varicella
chicken pox, highly contagious, peak in march, april and may, airborne or vesicular fluid, contagious 2 days before onset until all lesions have crusted, confers life long immunity, latent in ganglia on neuraxis
39
clinical course of varicella
incubation- 9-21 days, prodromal- fever, HA, malaise, eruptive phase- lesions up to 4 days, crusting by 6 d, 2-4 mm red papule, develop irregular outline, a thin walled clear vesicle appear on surface, begins on trunk-> face
40
Congenital or neonatal varicella
1st tri- limb hypoplasia, chorioretinitis, cortical atrophy, scars; 2nd tri- undetected fetal chickenpox, near birth- if mom has 2-3 weeks before delivery, fetus born w/ develop lesions 1-4 days after birth, mortality 20%, give ZIG or VZIG or gamma globulin
41
Lab diagnosis of varicella
culture, difficult due to labile virus, serologic testing- presence of IgG- past exposure, IgM- recent infection, Tzanck smear- rapid diagnosis, multinucleated giant cells
42
Treatment of varicella
vaccine- live attenuated, recommended for all above 12 months or older, prevented chicken pox in 85%, 97% against severe, acyclovir, or Foscarnet if resistant
43
Herpes zoster
shingles, cutaneous viral infection around dermatomes, 10-20% risk, inc w/ age as T-cell immunity to virus wanes, zoster results from reactivation of varicella virus in dorsal root ganglia
44
Clinical presentation
preeruptive pain, itching, burning, generally localized to dermatome, precedes eruption by 4-5 days, may simulate pleurisy, MI, abd disease, HA, may have prodromal sx
45
Zoster sine herpete
segmental neuralgia w/out any cutaneous eruption
46
Clinical features of shingles
eruptive- red swollen plaques, various sizes, spreads to dermatome, clusters w/ red base w/ purulent fluid 3-4 days, thoracic region, does not confer immunity, pain is neuropathic
47
Complications of shingles
pain persisting, can persists for m-y, encephalitis, immune mediated rather than result of virus
48
Treatment of shingles
suppress inflammation, pain and infection, antivirals in 72 hrs, valtrex 3-5 times bioavailability, wet compress 20 min several x/day; topical steroids, topical acyclovir, NSAIDs/lidocaine patch, TCA/gabapentin, opioids
49
Dermatophyte infection
ability to infect and survive on dead keratin, classified by body region
50
Diagnosis of fungal infection
KOH wet mount prep, most important test, direct visualization of hyphae in keratinized material, should obtain sample w/ 15# blades, fungal culture esp for hair and nail, woods light exam, light rays w/ wave-length >365 are produced when UV projected through woods filter
51
Tinea pedis types
most common are by drmatophyte, toe web infection, chronic, scaly infection of plantar surface, acute vesicular tinea pedis, two feet one hand syndrome
52
Toe web infection
tight fitting shoes compress toes- warm moist environment
53
chronic scaly infection of plantar surface
plantar hyperkeratosis particularly chronic and resistant to treatment
54
acute vesicular tinea pedis
acute form of infection often originates from more chronic web infection
55
Two feet-one hand syndrome
nails may be involved, common in males, t rubrum is causative organism
56
Treatment of tinea pedis
topical- lamisil cream, econazole, ketoconazole, oral antifungals, griseofulvin, fluconazole, itraconazole
57
Pitted keratolysis
disease mimicking tinea pedia, an eruption ofwt bearing surface, hyperhirosis most common sx, malodor and sliminess, bacterial in origin, circular/ longitudinal, punched out depressions, bacteria secrete keratinase
58
Treatment of pitted keratolysis
promote dryness, change socks frequently, 20% drysol, 10% formaldehyde, alcohol based benzoyl peroxide, topical abx may help
59
Tinea cruris
Jock itch, common in men, unilateral and in crural fold, half moon shaped plaque forms as a well defined scaling border and advances into thigh, occasionally but/ gluteal cleft, usually not scrotum
60
Treatment of tinea cruris
topical steroids often modify clinical presentation, topical antifungal, oral antifungal if not response
61
Tinea of scalp
most frequent 3-7 yo, originates from contact w pet or infected person, hair shaaft infection preceded by infection of scalp, because of cuticle fungus has to circumvent and go deeper, hyphae growth=hair growth
62
Clinical features of tinea of scalp
alopecia/ lymphadenopathy, kerion- boggy, indurated, tumor like mass that exudes pus, severe inflammatory rxn, scarring may occur, also present as black dot pattern, seborrheic dermatitis type, pustular type
63
Treatment of tinea of scalp
diagnose w/ KOH wet mounts, culture or woodslamp, griseofulvin is drug of choice, terbinafine, itraconazole
64
Candidiasis
lives w/ normal flora of mouth, infects only outer layer of epithelium of mucous membranes and skin, primary lesion is a pustule, clinically appears as red, denuded, glistening surface w/ long, scaling border, white curdy material
65
Oral candidiasis
Thrush, manifestation of HIV, self limiting in healthy newborns, adults- depressed CMI, leukemia, broad spectrum abx, steroids and diabetes, perleche- involvement of corner of mouth, vit B12 def
66
Treatment of oral candidiasis
fluconazole first line, itraconazole, ketoconazole, nystatin oral suspension
67
Monilial vulvovaginitis
>50% of women >25 develop, 30% tx w/ abx, vaginal itching, white discharge, red, swollen, painful genitals, satellite lesions
68
Treatment of monilial vulvovaginitis
Topical antifungals, miconazole, clotrimazole, terconazole, nystatin, oral antifungals fluconazole, itraconazole and ketoconazole, do not give to pregnany pts
69
Candidia of large skin folds
under breasts, groin, rectal area, contains heat, hot humid weather, tight underclothing, poor hygiene, first type-pustules, but macerate and form red papules w/ scales; second- red, moist, plaque extends beyond folds, wave shaped fringes
70
Treatment of candidia of large skin folds
Educate about yeast, dry area, wet compresses to promote dryness, antifungal creams, absorbent powers- difficult to clean
71
Diaper candidiasis
artificial intertriginous area is created under a wet diaper, treat by drying, change frequently, antifungal creams 2x daily, baby powders, mupirocin 2% cream if bacterial infection noted, erythema treat w/ 1% hydrocortisone
72
Tinea versicolar
pityrosposum orbiculare and p ovale, areas w inc sebaceous activity, in stratum corneum and hair follicles where thrives on FFA and TGA, cushings, preg, malnutrition, immunsuppression, common during higher sebaceous activity
73
Clinical features of tinea versicolar
mostly cosmetic, multiple small macules (varying colors), melanocyte damage basis of hypopigmentation, more obvious in nontanned regions, affects trunk, upper arms, neck, face in children, no sx, darker in blacks
74
Diagnosis of tinea versicolar
KOH prep, hyphae and spores, wood light, irregular pale yellow to white fluorescence
75
Treatment of tinea versicolar
ketoconazole 2% shampoo daily x3d, selenium sulfide 2.5% x 7 d, lamisil spray, itraconazole 200 mg x 7 d, difucan 300 mgx1 dose and repeat in 2 w, ketoconazole 400 mgx 1 dose, takes 6-8 weeks for pigment to return