Itchy anal rash with pilonidal sinus.

I have been diagnosed with a pilonidal sinus, and a general surgeon has examined me and recommended surgery. I also have red, itchy skin around the anal opening and the surrounding area. The itching is still present. I had previously used Castor MF occasionally, but I haven't been applying it recently, and the itching has continued. There is no bleeding or pain during bowel movements. Since I am going to have surgery for the pilonidal sinus, I would like to know: Could the redness and itching be a fungal infection or simple skin irritation? Is it safe to use a simple antifungal cream such as clotrimazole around the anal area, or should I use something else? Should I discuss this specifically with my surgeon before the surgery? Thank you.