Bacterial and Viral Skin Infections

Question 1

Name this and complications

Answer 1

Impetigo

Contagious superficial skin infection - Strep, Staph, or combo

Tx: Bactroban, oral Abx if severe

-Bactrim, Clinda, Doxy (have to cover for MRSA)

Complication: Post-strep glomerulonephritis - weeks after initial

Question 2

Meningococcemia

Answer 2

Neisseria meningitis - commonly 6mo-3yo

Most rapidly lethal form of septic shock

Pink 2-10 mm macules/papules on trunk, legs, face, palate, conjunctiva early w/ late petechia in macule center, hemorrhagic/purpuric lesions

-Kids die quickly of hemorrhage and Waterhouse-Fridreckson (endocrine emergency - no SNS response)

Tx: Cefotaxime, Ceftriaxone, Hemodynamic stabilization

Question 3

Bacterial Endocarditis

Answer 3

Staph aureus (most common), Strep viridans, Fungus (IVDU)

Strep is more indolent - low-grade fever for 4-6 wks before other sx

Fever, hematuria, splenomegaly, emboli = Endocarditis until proven not

Janeway lesions, Oster’s node, subungual splinter hemorrhages, petechial lesions

Tx: PCN-G, Nafcillin, Gentamycin, Vanco/Zyvox for MRSA

Question 4

Janeway lesions

Osler’s nodes

Subungual splinter hemorrhage

Petechial lesion

Answer 4

Janeway lesions: non-tender, hemorrhagic maculopapular lesions on palms and soles

Osler’s nodes: Painful red nodules on fingertips

Subungual splinter hemorrhage: Proximal ones are pathologic

Petechial lesion: small, nonblanching, red/brown macules on extremities, upper chest, mucus membrane

-also get red streaks in nails

Question 5

Rocky Mountain Spotted Fever

Answer 5

Rickettsia rickettsii - Hx tick bite in 60% cases

Prodrome: anorexia, irritable, malaise then fever, HA, photophobia after 1-2 wks

Rash from secondary phenomena - 2-6mm blanching macules which starts @ extremities and spreads centrally

-evolves to papules/petechiae in hours/days

Tx: Doxy, Chloramphenicol if Pregnant

Question 6

Lyme Disease

Answer 6

Multi-stage, multi-system infection from Borrelia burgdorferi

Rash hours/weeks, small/large - can mimic other skin dx - itchy, hot, or asx

Tx: Doxy (>8yo), Amoxicillin for kids, pregnant, breast-feeding

Question 7

Cellulitis

Answer 7

Staph aureus and GABHS common

Common in diabetes, elderly, PVD

Non-palpable cellulitis w/ warm erythema and deep edema

-Violaceous cellulitis w/ bullae = Staph pneumo infection

Tx: Mild - Bactrim/Clinda/Doxy for MRSA

-Complicated - Admit, empiric Abx - cover for MRSA - Ancef, Zyvox

Question 8

Erysipelas

Answer 8

GABHS - small erythematous patch progresses to fiery-red indurated shiny plaque - St. Anthony’s fire w/ lymphatic involvement

Sharply demarcated borders

Malaise, chills/fever, prodrome w/ several spots of redness & tenderness

Tx: PCN-G/VK, Keflex, Clinda, Erythromycin

Question 9

Human Bites

Dog/Cat Bites

Answer 9

Human bites - think anaerobes

-Tx: Augmentin, Avelox (>18 yo), Clindamycin, Tetanus, f/u 1-2 days

Dog/Cat Bites - cats = pasturella

Delayed closure for LE wounds

Tx: Augmentin, Erythromycin, Bactrim, Clinda, Cipro

Question 10

Necrotizing fasciitis

Answer 10

Hemolytic strep gangrene - progressive, rapidly spreading inflammatory infection in deep fascial plane w/ secondary necrosis of subcutaneous tissue

Tissue necrosis, putrid discharge, bullae, gas production, rapid burrowing

Tx: PCN-G, Flagyl, Clinda

Question 11

Hidradenitis Suppurativa

Answer 11

Chronic suppurative dx of apocrine gland-bearing skin

Onset usually around puberty - Axilla & anogenital region

Hx intermittent pain & marked tenderness w/ abscess formation

Tender, red inflammatory nodules that drain purulent/seropurulent material, fibrosis, bridge scars, lesions may become infected

Tx: Intralesional glucocorticoids, PO prednisone, I&D as last resort

-Oral Abx - erythromycin, tetracycline, minocycline

Question 12

Varicella

Answer 12

Contagious from 2 days before rash onset and until all lesions crusted over

“dew-drops on a rose petal”

Tx: Benadryl, Tylenol, Acyclovir

Question 13

Herpes Zoster (Shingles)

Answer 13

Along dermatomes - reactivation of varicella virus

Unilateral, very painful

Complications: post-herpetic neuralgia, Temporary motor paresis

Tx: Famvir, Valtrex, Acyclovir

Question 14

Genital Warts

Answer 14

Condyloma acuminate/Venereal warts

Papilloma virus - high evidence of relationship w/ genital cancer

Tx: Podophyllum 20% w/ benzoin tincture, Trichloroacetic acid

-Always treat, doesn’t ensure entire wart elimination - always f/u

Question 15

Molluscum Contagiosum

Answer 15

Poxvirus

Discrete 2-5 umbilicated, dome-shaped papules

Common in face, trunk, extremities in kids

Common in genital and pubic areas in adults

Tx: Self-limited in kids; Curettage, cryosurgery, TCA/podophyllum