• It is a contiguous, superficial pyogenic infection of skin
  • Pyodermas are infection in epidermis, just below the stratum corneum or in hair follicles.
  • Two main clinical forms
  • Bullous impetigo caused by S. aureus mostly
  • Nonbullous impetigo (or impetigo contagiosa or Tilbury Fox) may be caused by Staphylococcus aureus (most common); by group A-beta haemolytic streptococci (mainly in developing nations) or by both.
  • Most commonly affects children
  • Most common bacterial infection of children
  • Occurs in all age including adults and neonates (called pemphigus neonatorum)
  • Spread by close contact (contagious).
  • Bullous impetigo
Bullae are less rapidly ruptured
  • Larger (1-2cm)
  • Persist for 2-3 days
  • After rupture thin, flat brownish crusts are formed.
Streptococcal impetigo may lead to
  • Post streptococcal acute glomerulonephritis (AGN)
  • Scarlet fever
  • Erythema multiforme
  • Rheumatic fever is not a complication of streptococcal impetigo
  • Caused by Staphylococcus aureus and/or beta hemolytic Streptococci
  • It is mostly a disorder of prepubertal children
  • Initial lesion is a very thin walled vesicle on an erythematous base which ruptures so rapidly that its seldom seen
  • Gradual, irregular, peripheral extension occurs without central healing
  • Lesions are usually not painful, heals without scarring, no fever and patient is not ill
  • Characteristic feature
  • Golden or Honey colored crust
  • Neutrophils beneath stratum corneum
  • Face around nose and mouth) and limbs are most commonly affected
Exam Question
  • A 3 year old child is seen by a pediatrician because he has developed multiple isolated lesions on his face and neck. Physical examination reveals many lesions up to 4 cm in diameter with golden crusts, while in other sites small blisters and weeping areas are seen.Impetigo is the most likely diagnosis.
  • Impetigo contagiosa may be caused by Staphylococcus aureus (most common) or Group A beta hemolytic streptococci or by both.
  • Bullous impetigo caused by S. aureus mostly
  • Impetigo may predispose to glomerulonephritis.
  • Impetigo does not produce scar on healing.
  • Commonest skin infection in children is Impetigo Contagiosa.
  • 'Honey colored' crusts are characteristic of Impetigo.
  • Impetigo is a contagious bacterial infection.
  • Impetigo is a pyoderma.
  • Treatment for impetigo is Dicloxacillin.
  • Pigment production by staphylococcus aureus occurs in Bullous Impetigo.
  • Nikolsky's sign is seen in Bullous Impetigo.
Don't Forget to Solve all the previous Year Question asked on Impetigo