Rashes

Rapid Review

• Febrile
  • Varicella
  • Hand-foot-and-mouth disease
  • Necrotizing fasciitis
  • Disseminated gonococcal disease
  • Purpura fulminans
  • Disseminated intravascular coagulopathy (DIC)
  • Staph Scalded Skin Syndrome (SSSS)
  • Toxic Epidermal Necrolysis (TEN)
• Afebrile
  • Bullous pemphigoid
  • Pemphigus vulgaris
  • Contact dermatitis
  • Herpes zoster
  • Dyshidrotic eczema
  • Burns
• History
  • Recent new medications
  • Rapid vs gradual onset
• Physical Exam
  • Diffuse or localized
    • Localized suggests contact dermatitis, herpes zoster, eczema, or coxsackie virus
  • Abnormal Vitals (tachycardia, hypotension)
    • Consider meningitis, DIC, endocarditis
  • Palpable vs Non-palpable
    • Non-palpable suggests thrombocytopenia or DIC
  • Positive Nikolsky sign
    • Consider pemphigus vulgaris, SSSS, TEN
• Work-up
  • Labs
    • CBC, BMP, blood/urine cultures
    • Skin biopsy
      • If suspect SJS/TEN
    • PCR of DNA of vesicular fluid
      • If suspect varicella-zoster

Pearls

Deep Dive

• What’s that Rash? An approach to dangerous rashes (emDocs)

Rapid Review

• Differentials
  • Positive Nikolsky sign
    • Staph Scalded Skin Syndrome
    • Toxic Epidermal Necrolysis
  • Negative Nikolsky sign
    • Drug reaction w/ eosinophilia and systemic symptoms (DRESS)
    • Kawasaki
    • Scarlet fever
    • Anaphylaxis
    • Angioedema
    • Scombroid
• History
  • Fever/chills
  • Recent new food/drug exposure
  • History of allergies
• Physical Exam
  • Nikolsky sign
    • Narrows differential (see above)
  • Mucosal involvement
    • Consider angioedema, Kawasaki
• Work-up
  • CBC, BMP,
  • Skin biopsy
    • If suspect EM/SJS/TEN

Pearls

Deep Dive

• What’s that Rash? An approach to dangerous rashes (emDocs)

Rapid Review

• Differentials
  • Central distribution
    • Viral exanthem
    • Lyme disease
    • Drug reaction
    • Pityriasis
  • Peripheral distribution
    • Steven Johnson Syndrome (SJS)
    • Erythema multiforme
    • Meningococcemia
    • Rocky mountain spotted fever
    • Syphilis
    • Lyme disease
    • Scabies
    • Eczema
    • Psoriasis
• History
  • Fever/chills
  • Outdoor exposures
  • Recent viral infection
  • Recent new medication
• Physical Exam
  • Central vs Peripheral
    • Narrow differentials
  • Targetoid
    • Suggests erythema multiforme or lyme disease
  • Scaling
    • Consider scabies, tinea, psoriasis
• Work-up
  • CBC, BMP,
  • Skin biopsy
    • If suspect EM/SJS/TEN
  • Serologic testing for Lyme

Pearls

Deep Dive

Rapid Review

• Differentials
  • Febrile
    • Meningococcemia
    • Disseminated gonococcal infection
    • Henoch-Schlonein purpura
    • Rocky mountain spotted fever
    • Endocarditis
    • Disseminated intravascular coagulopathy (DIC)
    • Thrombotic Thrombocytopenic Purpura (TTP)
    • Hemolytic Uremic Syndrome (HUS)
  • Afebrile
    • Autoimmune vasculitis
    • Idiopathic thrombocytopenic purpura (ITP)
• History
  • Fever
  • Food exposure
  • Recent vaccines
  • Chronic illness
• Physical Exam
  • Abnormal Vitals (tachycardia, hypotension)
    • Consider meningitis, DIC, endocarditis
  • Palpable vs Non-palpable
    • Non-palpable suggests thrombocytopenia or DIC
• Work-up
  • Labs
    • CBC, Coagulation studies, D-dimer, fibrinogen level, CMP, blood cultures (if febrile/toxic)

Pearls

Deep Dive

• Petechiae (PubMed)