Pinworm (Enterobiasis) Differential Diagnoses

Updated: Feb 10, 2023
  • Author: Sun Huh, MD, PhD; Chief Editor: Michael Stuart Bronze, MD  more...
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Diagnostic Considerations

The diagnostic process usually is completed after hearing the symptoms of the infected person, including perianal itching, perianal pain,  insomnia, or diarrhea.

Diarrhea can be seen in the early stage of the pinworm infection. Diagnosis is based on the detection of eggs after the perianal swab with cellotape. However, the egg negative finding does not always indicate non-infection, because the false negative rate is high. The egg positive finding means that one female worm died after ovulation at the perianal area.  If a male worm stays in the caecum, it can not be detected. Also, if female worms are present in the large intestine, but do not migrate to the perianal area, eggs can not be detected. Therefore for more accurate diagnosis, repeat examination is required. If the worm burden is high, there is a chance of egg positive at the single exam. However, if the worm burden is low, the repeat exam is helpful for the diagnosis. [1, 2]

Differential Diagnoses