Erythematous rash

Background

• These rashes can occur in a variety of inflammatory and infectious conditions, some of which can be rapidly fatal

Rash Red Flags

• Fever
• Toxic appearance
• Hypotension
• Mucosal lesions
• Severe pain
• Very old or young age
• Immunosuppressed
• New medication

Clinical Features

• Characterized by diffuse red skin from capillary congestion, mimicking a bad sunburn.

Erythematous rash

• 

  Staphylococcal scalded skin syndrome

• 

  Toxic epidermal necrolysis

• 

  Kawasaki disease

• 

  Scarlet fever

• 

  Urticaria/anaphylaxis

• 

  Exfoliative erythroderma

• 

  DRESS

• 

  Cellulitis

• 

  Acute generalized exanthematous pustulosis

• 

  Drug eruption

• 

  Erythema multiforme

• 

  Vancomycin infusion reaction.

Differential Diagnosis

Erythematous rash

• Positive Nikolsky’s sign
  • Febrile
    • Staphylococcal scalded skin syndrome (children)
    • Toxic epidermal necrolysis/SJS (adults)
  • Afebrile
    • Toxic epidermal necrolysis
• Negative Nikolsky’s sign
  • Febrile
    • Toxic shock syndrome
    • Kawasaki disease
    • Scarlet fever
    • DRESS syndrome
    • Cellulitis
    • Acute generalized exanthematous pustulosis
  • Afebrile
    • Alcohol intoxication
    • Anaphylaxis
    • Cellulitis
    • Dermatitis (multiple types)
    • Drug rash
    • Erysipelas
    • Erythema multiforme
    • Exfoliative erythroderma
    • Scombroid
    • Vancomycin infusion reaction

Evaluation

Diagnosis

• First, try applying lateral pressure to the skin and see if it sloughs (Nikolsky’s sign)
• Then, to further narrow the differential, consider wither or not the patient is febrile or toxic in appearance
  • Patients with an erythematous rash plus fever are also at high risk for having a deadly diagnosis

See Also

• Rashes