Brief Answer:
Detailed below

Detailed Answer:
Hello!

Thank you for the query.

Perineal abscess does not describe exact location of the abscess. It simply means that the abscess is in the perineum. One of the perineum part is ischiorectal fossa. Its an anatomical space filled with fatty tissue located on the lowers part of the perineum. Abscess in this area can be called ischiorectal abscess.
So in simple words, there is no difference between perineal and ischiorectal abscess. However second name (ischirectal abscess) gives more precise location.

Hope this will help. Feel free to ask further questions.
Regards.

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Brief Answer:
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Detailed Answer:
The most common reason of such abscess is an infection of anal glands. Such infection can be triggered by diarrhea, anal intercourse or constipation.
Less common reasons are inflammatory bowels diseases like Crohns disease, Ulcerative Colitis or diverticulitis.
Recurring abscess can indicate the presence of pathological connection between the rectum and the skin called anal fistula.
As cellulitis is an inflammation of soft tissues without pus collection (abscess), the treatment is different than abscess treatment.
Cellulitis should be treated with antibiotics.
Abscess main treatment is an incision and drainage of it. Antibiotics can be given in case of weak immune system (patients with diabetes, leukemia).

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Brief Answer:
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Detailed Answer:
Either the abscess was not incised correctly or there is another one abscess.
Please note that rectal abscess treatment is not an easy thing. The incision has to be large enough (small incisions are mistake). Pus must be completely evacuated. If this does not help, proper diagnostics is necessary. Pelvis MRI should be done to determine if there is another/remaining pus collection.
WBC could be elevated before the abscess incision. The current level should be compared to previous result (the one before the incision).
Rapid worsening indicate infection spreading to surrounding tissues or even blood stream. Especially if the patient has diabetes.
It is hard to give exact path of diagnostics and treatment not being able to see the patient.
For sure, if its the first abscess he/she should have rectal examination done by experienced proctologist, rectoscopy or colonoscopy (depending of the patients age) to rule inflammatory bowels disease and rectal fistula. Transrectal ultrasound or pelvis MRI should be considered if the abscess is not healing well. Glucose level should be checked.
Swab test should be taken from incised abscess to determine which bacteria is causing it. If the abscess does not get healed, antibiotic treatment should be considered.

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Brief Answer:
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Detailed Answer:
Pain and elevated WBC can indicate that the drainage might be ineffective. Therefore mentioned before tests should be done (pelvis MRI). It does not have to be right away, but this should not wait no longer than a day or two. If MRI will confirm another abscess or some other problem, another surgery will be necessary.
Proctologist is the best type of surgeon in case of such problems.
Additional complication usually appear in the patients with weak immune system or with diabetes. However most of such abscesses should not cause additional complications even if not healed property. So this is not common.

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