I'm sorry to hear of this with Heidi. Has a vulvar fold dermatitis been diagnosed? The symptoms of this include erythematous (reddened), macerated, and malodorous vulvar folds, excessive vulvar licking, and painful urination. A secondary urinary tract infection may be present in these dogs which will need to be treated before the vulvar skin infection can resolve. There's a good chance that Heidi can't be cured with any antibiotic - even a human style z pac - unless she has excess vulvar folds surgically removed (vulvoplasty). For helpful conservative care please see the following:
1) A weight redeuction program should be initiated if Heidi is obese.
2) Cleansing wipes (i.e., alcohol-free acne pads, baby wipes, chlorhexidine-containing pledgets, other antimicrobial wipes) used every 12-72 hours work very well.
3) Alternatively, routine topical therapy can be used to control the skin problem The affected area should be cleaned every 1-3 days as needed with an antibacterial shampoo that contains chlorhexidine, benzoyl peroxide, or ethyl lactate. These shampoos are available over the counter in pet/feed stores, online, or at Heidi's vet hospital.
4) Topical application of an antibiotic ointment (over the counter triple antibiotic ointment), solution, or spray every 24 hours for the first 5-7 days of therapy may be helpful.
5) Make sure that the urinary tract is sterile. Her vet will want to obtain urine by cystocentesis - percutaneous aspiration of Heidi's bladder through Heidi's abdominal wall - the most sterile manner in which to obtain urine and then perform a complete urinalysis.
6) Surgery as mentioned above may be necessary.
7) The prognosis is good but lifelong topical maintenenace terapy may be needed if surgical correction isn't performed.
Please respond with further questions or concerns if you wish.