Dermatology Essentials

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Dermatology-focused and designed for recall and retention

Made for general practice, primary care, urgent care, and emergency providers

Topics include:

Soft Tissues Infections
Deadly Rashes
Skin conditions not to miss
Foot ulcerations
Pressure Sores/Wound Care
Pediatric Rashes
Common Treatments

Dermatology and Skin Library

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Erythema Marginatum

Erythema Multiforme

Vibrio Vulnificus

A collection of common skin findings designed for review, comparison, and rapid recall.
Includes treatment options and clinical pearls
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Summary Flashcards

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Boil down complex concepts into bite-sized pieces
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Inpatient and Outpatient Management Guidelines

Keep current with well organized guides for patient management
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Quick reference and workup guides
Regularly updated, with indexed evidence-based sources

Dermatology Overview

Dermatology Essentials

Cellulitis: infection of dermis and subcutaneous fat

Impetigo: superficial purulent lesions, esp. on face and extremities. Commonly with bullae and/or golden crust

Erysipelas: raised erythematous lesion with clear borders

Folliculitis: hair follicle inflammation. Superficial and limited to the epidermis.

Furunculosis: hair follicle infection that extend to dermis. Multiple = carbuncle

Necrotizing Infection: Deeper SSTI that involve fascial and/or muscle compartments

Microbiology

Cellulitis: primarily Staph and Strep, incl. MRSA. In immunocomp./diabetics, GNRs also
- Other etiologies: cat/dog bite P. moltocida; gardening Sporothrix; salt water Vibrio vulnificus; puncture wound → Pseudomonas
Impetigo: Strep or Staph
Erysipelas: group A Strep usu.
Folliculitis/furunculosis: S. aureus, Pseudomonas
Necrotizing Infections: Polymicrobial (eg strep and GNRs in Type I, Fournier’s), Group A Strep, S. aureus, Aeromonas hydrophila, Vibrio vulnificus

At risk: athletic teams, military, prison, MSM, communities with MRSA infxn, Diabetic

High risk for more aggressive infection: splenectomy, immunocompromised

Differential Diagnosis

Cellulitis
Impetigo
Erysipelas
Folliculitis
Furunculosis
Necrotizing fasciitis
Myonecrosis
Calciphylaxis
Cutaneous metastasis from neoplasms (especially adenocarcinoma)
Graft-versus-host disease (in appropriate population)
Sweet syndrome

Recent trauma to the affected area?
Any recent surgeries (hip replacement is risk factor)?
Ask about the presence of HIV, diabetes, liver disease, or kidney disease.
History of IV drug abuse or subcutaneous injection.
Recurrent Cellulitis: Assess for predisposing conditions such as edema, obesity, eczema, venous stasis, and toe web abnormalities.
Recurrent Abscesses: Search for local causes such as pilonidal cyst, HS, or foreign body. Consider 5-day decolonization (intranasal mupirosin, daily chlorhexidine). Consider neutrophil disorder if abscesses began in childhood.

Evaluate affected area for erythema, edema, warmth, and pain on palpation.
Look for lymphangiitis (erythematous tracks under the skin marking an inflamed lymphatic system), palpate for lymphadenopathy.
Assess for evidence of necrotizing infection: systemic toxicity with high temperature, hypotension, disorientation, lethargy, skin discoloration or bullous lesions, anesthesia, firm skin with wooden-hard induration, pain extending beyond cutaneous erythema, pain out of proportion to exam

Note: Diagnosis is largely clinical

Laboratory:

CBC with diff, ESR/CRP if concern for osteo, CK if concern for necrotizing infection or pyomyositis.
Furuncle/pustule can be aspirated for gram stain and culture.
For cellulitis, blood cultures are generally low yield, but should be obtained in patients undergoing chemo, neutropenic patients, and those who suffered animal bites.

Imaging:

If concern for osteo, xray; consider MRI
If concern for necrotizing infection can look for gas in fascial planes on x-ray or CT, but this is highly insensitive

More serious presentations of skin and soft tissue infections:

Toxic shock syndrome: fever, HA, vomiting, myalgias, pharyngitis, diarrhea, diffuse rash with desquamation. Hypotension and shock.
Osteomyelitis: infection of bone due to hematogenous seeding or direct spread from overlying focus.
Necrotizing fasciitis: infection and necrosis of superficial fascia, subq fat, and deep fascia. Clues: rapidly spreading cellulitis, systemic toxicity (inc TSS), pain out of proportion to exam, bullae formation, gangrene, crepitus. Surgical and medical emergency.
Gas gangrene: Clostridial myonecrosis, a fulminant skeletal muscle infection. C. perfringins usually in the setting of trauma; C. septicum in setting of cancer. Surgical and medical emergency.

Purulent (furuncle/carbuncle/abscess):

Mild: I & D
Moderate: I & D, send for culture and sensitives
- Empiric treatment: Bactrim 1-2 DS tab BID or Doxycycline 100mg BID
- Defined treatment: MRSA: Bactrim 1-2 DS tab BID, MSSA: Dicloxacillin 250 Q6H or Cephalexin 500 Q6H or Cefadroxil 500mg po q12.
Severe: I & D, send for culture and sensitiivies
- Empiric treatment: Vancomycin or Daptomycin or Linezolid or Ceftaroline
- Defined treatment: MRSA: similar to empiric, MSSA: Nafcillin or Cefazolin or Clindamycin (if Susceptible)

Nonpurulent (necrotizing infection/cellulitis/erysipelas):

Mild: impetigo: topical mupirocin; oral treatment: Penicillin VK or Cephalosporin (eg Cephalexin 500mg PO Q6H) or Dicloxacillin 500mg PO Q6H or Clindamycin 300mg PO Q8H
Moderate: IV therapy: penicillin or Cefriaxone or Cefazolin or Clindamycin 300mg PO Q8H or 600mg IV Q8H
Severe: emergency surgical evaluation/debridement to rule out necrotizing process
- Empiric treatment: Vancomycin PLUS Piperacillin/Tazobactam
- Defined treatment for necrotizing infections:
  - Strep. pyogenes:Penicillin PLUS Clindamycin
  - Vibrio vulnificus:Doxycycline PLUS Ceftazidime
  - Aeromonas hydrophila:Doxycycline PLUS Ciprofloxacin
  - Polymicrobial: Vancomycin PLUS Piperacillin/Tazobactam

Duration of Therapy: 5-7 Days

Treatment Notes:

– Erythema may initially worsen with antibiotics 2/2 local bacterial killing.

– For cellulitis, elevation of the affected extremity is essential to treatment.

– For Staph aureus infections (eg suppurative cellulitis) in 2014 at Hopkins susceptibilities were: TMP-SMX 87-88%, Tetracycline 89-91%, and Clindamycin 46-60%.

– For Beta-hemolytic Strep infections (eg non-suppurative cellulitis) all strains are susceptible to penicillin. At Hopkins there are high rates of resistance to TMP-SMX and tetracyclines and variable rates of resistance to Clindamycin.

– If you are concerned for a necrotizing infection, CONSULT SURGERY. Empiric antibiotic treatment with vancomycin (or linezolid) PLUS zosyn (or carbapenem) should be initiated. Clindamycin can be added to inhibit toxin production.

Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clin Infect Dis. 2014;59(2):e10-52. [PMID:24973422]
Swartz MN. Clinical practice. Cellulitis. N Engl J Med. 2004;350(9):904-12. [PMID:14985488]