3/12/19 Cutaneous Infections (and their mimickers) Disclosures I - - PDF document

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3/12/19 Cutaneous Infections (and their mimickers) Disclosures I - - PDF document

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3/12/19 Cutaneous Infections (and their mimickers) Disclosures I have no conflicts of interest to disclose. I may discuss off-label use of treatments for cutaneous disease. Kanade Shinkai, MD PhD Professor of Clinical Dermatology University

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3/12/19 1

Cutaneous Infections (and their mimickers)

Kanade Shinkai, MD PhD Professor of Clinical Dermatology University of California, San Francisco

Disclosures

I have no conflicts of interest to disclose. I may discuss off-label use of treatments for cutaneous disease.

A preview

  • Image review: Classic skin presentations of infections (and

mimickers). Part 1.

  • Speed rounds: the red leg
  • Image review: Classic skin presentations of infections (and

mimickers). Part 2.

Classic cutaneous presentations

  • f infectious diseases (and mimickers)

Part 1. 18 year old, immunosuppressed for MCTD Rash not responding to topical steroids

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Best first test to be performed in clinic:

1 Bacterial culture 2 Viral culture 3 Viral direct fluorescence antibody (DFA) 4 Skin biopsy 5 KOH test

Best first test to be performed in clinic:

1 Bacterial culture 2 Viral culture 3 Viral direct fluorescence antibody (DFA) 4 Skin biopsy 5 KOH test

Annular scaly eruption with central “clearing” Tinea corporis

Trichophyton rubrum Trichophyton mentagrophytes Microsporum canis (inflammatory) Microsporum audouinii Diagnosis: KOH Morphology on mold cultures (low yield) Lactophenol plates (higher yield) Skin biopsy (PAS-D)

HIV+ man, CD4 nadir = 4 Most likely infection is:

1 Molluscum contagiosum 2 Cryptococcus neoformans 3 Pseudomonas aeruginosa 4 Herpes simplex virus 5 Penicillium marneffei

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Most likely infection is:

1 Molluscum contagiosum 2 Cryptococcus neoformans 3 Pseudomonas aeruginosa 4 Herpes simplex virus 5 Penicillium marneffei

Molluscum contagiosum All except for pseudomonas are in the differential diagnosis in setting of HIV+, CD4<50

1 Molluscum contagiosum: umbilicated papules 2 Cryptococcus neoformans: umbilicated papules 3 Pseudomonas aeruginosa 4 Herpes simplex virus: unusual morphology in immunosuppressed patients 5 Penicillium marneffei: umbilicated papules

Please note: This is not an ARS question

Chronic atopic dermatitis with acute flare Best first test to be performed in clinic:

1 Bacterial culture 2 Fungal culture 3 Viral direct fluorescence antibody (DFA) 4 Skin biopsy 5 KOH test

Best first test to be performed in clinic:

1 Bacterial culture 2 Fungal culture 3 Viral direct fluorescence antibody (DFA) 4 Skin biopsy 5 KOH test

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Eczema herpeticum

J Murase, MD

SLE on prednisone, mycophenolate mofetil Best diagnosis is

1 Acne vulgaris 2 Steroid-induced acne/ folliculitis 3 Rash of systemic lupus erythematosus 4 Demodex folliculitis 5 Staphylococcal folliculitis

Best diagnosis is

1 Acne vulgaris 2 Steroid-induced acne/ folliculitis 3 Rash of systemic lupus erythematosus 4 Demodex folliculitis 5 Staphylococcal folliculitis

Demodex folliculitis in rosacea Demodex folliculorum, Demodex brevis

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Bedside test Immunosuppressed liver transplant recipient Most likely infectious cause is

1 Staphylococcus aureus 2 Streptococcus viridans 3 Borrelia burgdorferii 4 Bartonella henselae 5 Vibrio vulnificus 1 Staphylococcus aureus 2 Streptococcus viridans 3 Borrelia burgdorferii 4 Bartonella henselae 5 Vibrio vulnificus

Most likely infectious cause is Common d/dx of vascular neoplasm

  • Hemangioma/ angiomas
  • Glomus tumors
  • Kaposi Sarcoma
  • Bacillary angiomatosis
  • Pyogenic granuloma
  • Angiosarcoma
  • Melanoma (amelanotic)
  • Spitz tumor
  • Squamous cell carcinoma

Immunosuppressed SCT recipient

B Schwartz, MD

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Most likely cause is

1 Nocardia asteroides 2 Fusarium oxysporum 3 Herpes simplex virus 4 Leukemia cutis 5 Squamous cell carcinoma

Most likely cause is

1 Nocardia asteroides 2 Fusarium oxysporum 3 Herpes simplex virus 4 Leukemia cutis 5 Squamous cell carcinoma

Immunosuppressed patient, 3 day ulcer

Ahronowitz I, Harp J, Shinkai K (2012) Am J Clin Derm, 13: 191-211

Most likely cause of a rapid-forming ulcer is:

1 Factitial ulcer 2 Pyoderma gangrenosum 3 Herpes simplex 4 Pseudomonas aeruginosa 5 Capnocytophaga canimorsus

Most likely cause of a rapid-forming ulcer is:

1 Factitial ulcer 2 Pyoderma gangrenosum 3 Herpes simplex 4 Pseudomonas aeruginosa 5 Capnocytophaga canimorsus

Pyoderma gangrenosum

Inflammatory (not infectious) ulcer with neutrophils Diagnosis of exclusion Violaceous rim, undermined border Can begin with pustule or boil Pathergy: triggered by (or worsens with) trauma Associated with: inflammatory bowel disease malignancy (myeloma, IgA) connective tissue disease

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Ulcer with violaceous border, culture negative

Ahronowitz I, Harp J, Shinkai K (2012) Etiology and management of pyoderma gangrenosum, Am J Clin Derm, 13: 191-211 Ahronowitz I, Harp J, Shinkai K (2012) Etiology and management of pyoderma gangrenosum, Am J Clin Derm, 13: 191-211

1 Acute generalized exanthematous pustulosis 2 Streptococcus viridans 3 Coxsackie A6 virus 4 Herpes simplex virus 5 Varicella zoster virus

Most likely cause is

1 Acute generalized exanthematous pustulosis 2 Streptococcus viridans 3 Coxsackie A6 virus 4 Herpes simplex virus 5 Varicella zoster virus

Most likely cause is

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1 Herpes simplex virus 2 Erythema multiforme 3 Coxsackie A16 4 Varicella zoster virus 5 Chilblains lupus

Most common cause of “football” shaped vesiculopustules:

1 Herpes simplex virus 2 Erythema multiforme 3 Coxsackie A16 – Hand, foot, mouth disease 4 Varicella zoster virus 5 Chilblains lupus

Most common cause of “football” shaped vesiculopustules: Consult question: eczema management

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Best diagnosis is:

1 Severe atopic dermatitis 2 Psoriasis 3 Drug eruption 4 Retention hyperkeratosis 5 Scabies

Best diagnosis is:

1 Severe atopic dermatitis 2 Psoriasis 3 Drug eruption 4 Retention hyperkeratosis 5 Scabies

Scabies: sarcoptes scabei

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Speed rounds: the red leg Best diagnosis is:

1 Bilateral cellulitis 2 Bilateral erysipelas 3 Vasculitis 4 Venous stasis dermatitis 5 Pyomyositis

Best diagnosis is:

1 Bilateral cellulitis 2 Bilateral erysipelas 3 Vasculitis 4 Venous stasis dermatitis 5 Pyomyositis

D/dx of the red leg?

  • erysipelas
  • cellulitis
  • DVT
  • vasculitis
  • pyomyositis
  • necrotizing fasciitis
  • asteatotic dermatitis
  • stasis dermatitis
  • contact dermatitis

Red Leg: Speed rounds

No fever, no leukocytosis, bilateral itchy red legs

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Stasis dermatitis

Key features:

  • bilateral erythema, edema (L>>R)
  • varicose veins
  • brawny (golden) hyperpigmentation
  • no WBC, LAD, lymphangitis

Rx: compression topical steroids

Fever, leukocytosis, red leg

  • Unilateral
  • GAS, Staph aureus
  • Rapid spread
  • Toxic-appearing patient
  • WBC up, LAD, streaking

Cellulitis Fever, leukocytosis, red leg

  • Superficial cellulitis (leg, face)
  • Strep (GAS > GBS)
  • F>M
  • Involves lymphatics
  • Clue: raised, shiny plaques

Erysipelas Fever, leukocytosis, minimally red leg not responding to antibiotics

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Pyomyositis

  • bacterial infection of muscle
  • S aureus (77%), strep (12%)
  • risk factors:
  • trauma
  • travel (tropics)
  • immunocompromised
  • Dx: MRI
  • Rx: surgical drainage

psoas, gluteus, quadriceps*

Necrotizing fasciitis

  • Strep/ staph infection of fascia
  • post-surgical
  • 20% mortality
  • pain out of proportion to exam
  • rapid spread (minutes to hours)
  • Dx: MRI
  • Rx: surgical debridement

IV antibiotics

Fever, leukocytosis, bilateral red legs Vasculitis

  • Clue: palpable purpura (bumps!)
  • favors dependent areas
  • bilateral
  • fever, malaise, arthralgias
  • may involve vessels of other organs
  • kidneys, joints, gut
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No fever, no leukocytosis, but a red leg history of topical neomycin for rash Contact dermatitis

  • clue: red, angry, weeping, itch>pain
  • patient looks well
  • history is key
  • neomycin is top contact allergen
  • also:

poison oak (rhus) topical diphenhydramine

Red leg: Pearls

Not all red legs are cellulitis Bilateral cellulitis is rare. Reconsider diagnosis Many treatments for the red leg are exclusive

Classic cutaneous presentations

  • f infectious diseases (and mimickers)

Part 2.

1 Trichophyton rubrum 2 Fusarium oxysporum 3 Candida albicans 4 Penicillium marneffei 5 Pseudomonas aeruginosa

Superficial proximal onychomycosis due to:

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1 Trichophyton rubrum 2 Fusarium oxysporum 3 Candida albicans 4 Penicillium marneffei 5 Pseudomonas aeruginosa

Superficial proximal onychomycosis due to: Also note purple nodules of Kaposi sarcoma

1 Basal cell carcinoma 2 Pyoderma gangrenosum 3 Leishmania ulcer 4 Squamous cell carcinoma 5 Spider bite

Differential diagnosis includes all but:

1 Basal cell carcinoma 2 Pyoderma gangrenosum 3 Leishmania ulcer 4 Squamous cell carcinoma 5 Spider bite

Differential diagnosis includes all but:

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1 Skin biopsy 2 Liquid nitrogen 3 Topical imiquimod cream 4 Podophyllin 5 Reassurance

Best next step:

1 Skin biopsy 2 Liquid nitrogen 3 Topical imiquimod cream 4 Podophyllin 5 Reassurance

Best next step:

Bylaite M and Ruzicka T. N Engl J Med 2007;357:691

Pearly pink papules of the penis/ vulva Traveler to Costa Rica

1 Pyoderma gangrenosum 1 Herpes simplex virus 2 Mycobacterium marinum 3 Leishmania panamensis 4 Vasculitis

Differential diagnosis for this ulcer:

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1 Pyoderma gangrenosum 1 Herpes simplex virus 2 Mycobacterium marinum 3 Leishmania panamensis 4 Vasculitis

Differential diagnosis for this ulcer: 2nd case from Central America Pearls for clinical practice

  • Using skin morphology to make the diagnosis
  • Keep differential broad: infection & non-infectious causes
  • If it scales, scrape it (part I): tinea corporis
  • If it scales, scrape it (part II): scabies
  • Differential diagnosis of the red leg

Kanade Shinkai (kanade.shinkai@ucsf.edu)