Clinical features:
(1) pruritis ani
(2) constipation
(3) anal pain, especially on defecation
(4) blood in the stool and/or perianal bleeding
(5) erythema in the perianal skin, often with edema
(6) cracking of the skin and/or anal fissures
(7) A purulent exudates may be noted.
(8) Girls may have concurrent vulvovaginal infection.
Laboratory features:
(1) The culture will usually be positive for Streptococcus pyogenes. Less often a Group B, C or G Streptococcus may be isolated.
Reasons for a false negative culture:
(1) inadequate specimen
(2) application of a topical antibiotic cream
Differential diagnosis:
(1) It is important that the infection not be misdiagnosed as child abuse.
(2) pinworms
(3) lichen sclerosis et atrophicus
