Hi and thanks for the query,
Common probable causes of itching in the anus in this particular case shall be a hemorroid or an infected fissure. But it is more probable it should be a hemorroid. Other associated symptoms are important to consider. Any past history of this condition., any notion of chronic constipation
, past history of passing out blood in the past or not?
Parasitic infections that could also cause itching around the anus is the whip worm (Entorobius Vermicularis). Diagnosis shall be based on a clear physical examination of this area and probable doing a stool exam, and if necessary based on the clinical picture, a scrotch test to exclude the possibility of the whip worm infection
I suggest you consult your family physician for a good clinical evaluation and management.
Thanks and hope this helps,