Impetigo

Background

• Superficial epidermal infection characterized by amber crusts (nonbullous) or vesicles (bullous)
• May be super-infection or primary infection
  • Typical causative organisms are Staphylococcus aureus or Streptococcus pyogenes
• Fever and systemic signs are uncommon
• Post-streptococcal glomerular nephritis is a possible complication, and incidence is not reduced by antibiotic therapy
• Highly contagious and easily transmittable

Clinical Features

Impetigo honey-colored scab

Impetigo on the back of the neck.

Bullous impetigo after the bulla have broken.

• Nonbullous
  • Erythematous macules/papules develop into vesicles which become pustular and rupture
    • As rupture release yellow fluid which dries to form stratified golden crust
• Bullous
  • Bullae form as result of staph toxin
  • Some cases caused by MRSA
• Uncommonly painful, but usually pruritic
• Regional lymphadenopathy is common

Differential Diagnosis

Other Rash

• Acute generalized exanthematous pustulosis
• Allergic reaction
• Aphthous stomatitis
• Atopic dermatitis
• Coxsackie
• Dermatitis herpetiformis
• Exfoliative erythroderma
• Impetigo
• Pellagra
• Pityriasis rosea
• Serum Sickness
• Tinea capitus
• Tinea corporis
• Vitiligo

Evaluation

• Clinical diagnosis

Management

Antibiotics

Coverage for MSSA, MRSA, Group A Strep

Topical therapy

• Mupirocin (Bactroban) 2% ointment q8hrs x 5 days
  • For nonbullous impetigo, topic antibiotics are as effective as oral antibiotics

Oral Therapy

• Cephalexin 500mg (6.25mg/kg) PO q6hrs for 10 days OR
• Amoxicillin/Clavulanate 875mg (12.5mg/kg) PO q12hrs daily x 10 days OR
• Clindamycin 450mg PO q8hrs daily (or 10mg/kg PO q6hrs) for 10 days OR
• Dicloxacillin 500mg (3mg/kg) PO q6hrs daily x 10 days

Disposition

• Outpatient

See Also

• Rash