impetigo

Synopsis

 pustuleis filled with neutrophils
 cleavage plane is subcorneal or upper granular layer
 variable acantholysis

• neutrophils may be seen in the spongiotic stratum spinosum

 bacterial clusters are evident with Gram stain
 dermal infiltrate

• The underlying dermal infiltrate contains a mixed neutrophil and lymphocytes infiltrate

Differential diagnosis

 allergic contact dermatitis: different clinical history, extensive spongiosis, numerous eosinophils
 pemphigus

• Antibodies in a pemphigus like pattern: may be demonstrated in bullous impetigo and distinction from pemphigus foliaceous may therefore be a problem; generally the presence of numerous neutrophils and the recognition of Gram positive cocci is sufficiently characteristic of impetigo, as acantholytic cells are very scanty

 herpes simplex infection: different clinical history, viral inclusions
 insect bites: different clinical history
 Other blistering disorders: including chronic bullous dermatosis of childhood
 subcorneal pustular dermatosis and pustular psoriasis
 superficial variant of pemphigus: particularly as the latter become secondarily infected and there may be one or two acantholytic cells in impetigo
 thermal burns: different clinical history

See also

 bullous diseases